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In spite of the importance of the corpus luteum in human reproduction, little is known about its formation after ovulation and during regression in the absence of conception. This is largely due to constraints on the availability of normal human tissue: therefore an appropriate model which could be studied and provide information applicable to the human was sought. The baboon (Papio), a non-human primate, has been determined to be one such model. Thus, in the past several years our studies have examined the role of luteal peptides in corpus luteum function, and, when possible, we have attempted to examine corpora lutea from the human and baboon in parallel. Although a milk-ejection factor was recognized to be present in luteal tissue in 1910 (Ott and Scott, Proc. Soc. Exp. Biol. Med., Vol. 8, p 49), the role of oxytocin in luteal physiology has not been easy to ascertain. This is in part due to the methodologies employed to assess its role. Our studies summarized below suggest that oxytocin does not directly affect luteal steroidogenesis, but that it may play a role in cell to cell communication involving the expression of the gap junction proteins, the connexins. In view of the fact that oxytocin, its receptor, gap junctions and associated proteins are not unique to the human and non-human primates, the model of luteal development and demise proposed may be applicable to most species. [ABSTRACT FROM PUBLISHER]

Objective: This study was undertaken to investigate the effects of 17beta-estradiol (E2) on G1 cell cycle progression and proliferation in uterine fibroid and myometrial cells and the roles of phosphatidylinositol-3 kinase and mammalian target of rapamycin in mediating these estrogen effects.Study Design: The human uterine smooth muscle-derived cells (UtSM) and uterine leiomyoma-derived cells (UtLM) were treated with varying doses of E2 with or without pretreatment with LY294002, a phosphatidylinositol-3 kinase inhibitor, or rapamycin, a mammalian target of rapamycin inhibitor. The effects of E2 on cell cycle progression and proliferation and the roles of phosphatidylinositol-3 kinase and mammalian target of rapamycin in E2-induced effects were studied.Results: Compared with controls, E2 significantly induced G1 cell cycle progression and proliferation in uterine smooth muscle-derived cells and uterine leiomyoma-derived cells. These effects, however, were significantly blocked when LY294002 or rapamycin was used.Conclusion: E2 significantly induces G1 cell cycle progression and cell proliferation in uterine smooth muscle-derived cells and uterine leiomyoma-derived cells, in which phosphatidylinositol-3 kinase and mammalian target of rapamycin are essentially required. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The purpose of this study was to compare acetaminophen with ibuprofen for pain relief and menstrual fluid prostaglandin F2alpha (PGF2alpha) suppression in primary dysmenorrhea. STUDY DESIGN: Twelve subjects were randomized to placebo, acetaminophen (1000 mg orally, 4 x daily for 3 days) or ibuprofen (400 mg orally, 4 x daily for 3 days), once during each cycle in a prospective, double-blinded, crossover study. Using preweighed super absorbent tampons, menstrual fluid was collected, extracted, and PGF2alpha radioimmunoassayed. RESULTS: Ten patients completed the study. Ibuprofen (P = .002) and acetaminophen (P = .022) were rated significantly better than placebo. Total menstrual fluid PGF2alpha with placebo was 36.2 + 6.1 microg but were 14.8 + 3.0 microg with ibuprofen (P = .001) and 21.4 + 3.4 microg with acetaminophen (P = .008). PGF2alpha concentrations with placebo were 0.34 + 0.054 microg/mL, with ibuprofen 0.16 + 0.026 microg/mL (P = .001), and with acetaminophen 0.23 + 0.029 microg/mL (P = .016). CONCLUSION: Both ibuprofen and acetaminophen were superior to placebo for pain relief and menstrual fluid PGF2alpha suppression, with ibuprofen being more potent. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of oxytocin, its antagonist antocin, and agonist decomoton on baboon luteal cell P secretion., Design: Prospective study., Setting: Academic department of obstetrics and gynecology in a US medical school., Animal(s): Luteal-phased timed corpora lutea (CL) from a cohort of adult cycling baboons (Papio anubis)., Intervention(s): Dispersed luteal cells from luteal phase baboon CL were cultured and treated with nothing (control), oxytocin (4-400 mU), antocin (4-400 microg), oxytocin with antocin, decomoton (4-400 microg), or oxytocin with decomoton., Main Outcome Measure(s): Basal and hCG (10 U)-stimulated P were measured in the incubate., Result(s): Basal P secretion did not change significantly with all peptides studied. The hCG-stimulated P secretion was significantly inhibited by oxytocin (4-400 mU), antocin (4-400 microg), and antocin combined with oxytocin, and with oxytocin, decomoton, and decomoton combined with oxytocin. Antocin (-12%) was less inhibitory than oxytocin (-25% to -22%). Antocin combined with oxytocin enhanced the inhibition to -35% to -39%. Decomoton had stronger (not significant) inhibition than oxytocin. Mean inhibition was 28%-35% with all doses of oxytocin, decomoton, or combined together., Conclusion(s): Although decomoton, an oxytocin agonist inhibited hCG-stimulated luteal cell P secretion in vitro, antocin also acted like an agonist, rather than an antagonist, in inhibiting P secretion.

Objective: To determine the size of the baboon corpus luteum (CL) and levels of plasma P, 17alpha-hydroxyprogesterone (17-OHP), and E2 in the ovarian vein draining it, the contralateral ovarian vein, and peripheral blood throughout the luteal phase of the menstrual cycle., Design: Prospective study., Setting: Academic department of obstetrics and gynecology in a US medical school., Animal(s): Corpora lutea from a cohort of 27 adult cycling baboons (Papio anubis)., Intervention(s): Timed luteectomy., Main Outcome Measure(s): The authors weighed 166 CL and measured plasma P, 17-OHP, and E(2) in the blood samples obtained at luteectomy., Result(s): Early luteal phase corpora lutea weighed 189.1 +/- 12.3 mg (mean +/- SEM); their weight significantly increased to 239.4 +/- 8.4 mg at mid luteal phase and significantly declined to 188.3 +/- 14.0 mg in late luteal phase. Plasma P draining the CL (134.4 +/- 20.5 ng/mL in early, 167.4 +/- 18.7 ng/mL in mid, and 126.4 +/- 23.4 ng/mL in late luteal phase) was significantly higher than that in contralateral ovarian (11.0 +/- 1.4 ng/mL) and peripheral plasma (7.1 +/- 0.9 ng/mL). Similarly, levels of both plasma 17-OHP (10.9 +/- 1.5 to 15.9 +/- 2.4 ng/mL) and E2 (1.6 +/- 0.2 to 2.6 +/- 0.6 ng/mL) draining the CL were significantly higher than those from the contralateral ovary and peripheral blood (17-OHP, 1.1 +/- 0.2 ng/mL; E2, 0.2 +/- 0.05 ng/mL)., Conclusion(s): Largest in mid luteal phase, the baboon CL secretes P, 17-OHP, and E2 throughout the luteal phase, with the highest levels seen in the ovarian vein draining the CL in the mid compared with the early and late luteal phases.

Eleven women with primary dysmenorrhea completed a randomized, double-blind, placebo-controlled, three-way cross-over study comparing 200 and 400mg suprofen. Menstrual fluid volume did not change. Mean+/-S.E.M. menstrual fluid PGF2a was significantly suppressed from 18.9+/-1.9 microg (placebo) to 10.9+/-1.7 and 9.3+/-2.1 microg with 200 and 400 mg suprofen, respectively (p=<0.005). PGE2 dropped from 7.8+/-0.9 to 4.6+/-0.8 and 4.6+/-1.1 microg (p=<0.05) and TxB2 from 17.5+/-4.3 to 7.5+/-2.9 and 3.6+/-1.3 microg (p=<0.01), respectively. 6-Keto PGF1a was significantly suppressed (2.7+/-0.4 to 1.9+/-0.5 microg, p=<0.025) with only 400 mg suprofen. Six subjects rated placebo poor and five fair to very good. In contrast, nine rated suprofen excellent to fair while two rated poor. Thus, suprofen was clinically effective but the differential suppression of prostanoids favors 200mg which spares 6-keto PGF1a.

Objectives: This study was undertaken to determine expression levels of oxytocin receptor and its gene in peri-implantation phase human endometrium during clomiphene-treated cycles compared with control cycles., Study Design: Oxytocin receptor and its messenger ribonucleic acid in peri-implantation phase endometrium during control and clomiphene-treated (50 mg days 5 to 9) cycles of 5 healthy fertile women were determined by immunohistochemical methods, Western blot analysis with monoclonal antibody against amino acids 20 through 40 of the extracellular N-terminal human oxytocin receptor, and reverse transcription-polymerase chain reaction with oligonucleotide primers to amplify the 391-base pair fragment of the oxytocin receptor gene., Results: Oxytocin receptor and its messenger ribonucleic acid were expressed in human peri-implantation phase endometrial samples from both control and clomiphene-treated cycles. The receptor was localized predominantly in the epithelial cells and glands, with little or none detected in the stroma. Oxytocin receptor protein was separated out as a single 70-kd band by Western blot analysis; its relative abundance was significantly reduced during clomiphene-treated cycles. The messenger ribonucleic acid was detected in all endometrium during control and clomiphene-treated cycles, with greater expression during control cycles., Conclusions: The expressions of oxytocin receptor and its gene in luteal phase human endometrium suggest a functional relevance in modulation of biochemical changes for implantation.

Objective: The study determined the expression of oxytocin receptor and its gene in human uterine leiomyoma compared with the adjacent myometrium., Study Design: Paired samples of leiomyoma and the adjacent myometrium from 20 women through the menstrual cycle, menopause, and various hormone treatments were studied. Oxytocin receptor was immunohistochemically localized with use of the specific antibody (2F8) to human oxytocin receptor. Oxytocin receptor protein was determined by Western blotting, whereas reverse transcription-polymerase chain reaction was used for oxytocin receptor messenger ribonucleic acid expression., Results: Immunohistochemistry showed positive staining in all tissues examined, relatively more intense in the myometrium than in the adjacent leiomyoma, and in tissues from the preovulatory than the postovulatory phase. Western blotting showed a single 70-kd band corresponding to the oxytocin receptor. The relative abundance of oxytocin receptor in both leiomyoma and myometrium was significantly higher during the preovulatory (n = 5) than the postovulatory (n = 5) phase (P = .034 and .05). In women receiving gonadotropin-releasing hormone agonist (n = 1) or oral contraceptives (n = 1), after the menopause (n = 2), and with irregular vaginal bleeding (n = 1), oxytocin receptor levels in leiomyoma and myometrium were unchanged but were reduced in anovulatory cycles (amenorrhea, n = 2). Reverse transcription-polymerase chain reaction showed messenger ribonucleic acid for oxytocin receptor as a 391-bp band in all leiomyomas and myometrium examined., Conclusions: Leiomyoma and myometrium express the gene and protein for oxytocin receptor, which is probably partially regulated by ovarian sex steroids during the menstrual cycle.

Objective: The purpose of this investigation was to determine whether treatment with clomiphene citrate, which is estrogenic and antiestrogenic, affects the expression of the cell adhesion molecule E-cadherin in human periimplantation phase endometrium., Study Design: Five healthy women were studied for two cycles each, a control and a treated (clomiphene 50 mg daily, days 5 through 9) cycle. A biopsy specimen of endometrial tissue was studied (8 to 10 days post luteinizing hormone surge) for immunohistochemical localization, Western analysis of E-cadherin with use of a highly specific monoclonal antibody to human E-cadherin, and determination of messenger ribonucleic acid for E-cadherin by reverse transcription-polymerase chain reaction by use of oligonucleotide primers specific to E-cadherin and amplifying a 432 bp fragment., Results: Luteal phase plasma progesterone levels were significantly higher in clomiphene cycles. E-cadherin was immunocytochemically present in endometrium of control and treated cycles with no apparent difference in staining intensity. Western blots revealed the presence of E-cadherin. It was relatively more abundant in clomiphene-treated than control cycles but not significantly different. The message for E-cadherin gene is expressed in endometrium of control (n = 5) and clomiphene cycles (n = 4)., Conclusions: E-cadherin and its gene transcripts are expressed in periimplantation phase endometrium and are not significantly affected by clomiphene treatment.

Interleukin-1 beta (IL-1 beta) modulates steroidogenesis and prostaglandin (PG) secretion by dispersed luteal cells of some non-primate species. To determine if IL-1 beta affects progesterone (P) and PGF2 alpha secretion by the baboon corpus luteum (CL), we microretrodialyzed the intact CL for 48 h; 12 h media (baseline), 12 h with IL-1 beta (3 IU/h), 12 h media only (post- IL-1 beta) and 12 h with cAMP (5 nmol/h). Four CL from the midluteal phase (LH + 8 days) were studied. P was measured by a sensitive and specific radioimmunoassay and PGF2 alpha by an enzyme immunoassay in the 10-min fractions of retrodialysates collected. P secretions were analyzed for peaks by PC Pulsar (3.0) and total P retrieved/12 h for each experimental segment was calculated. P secretion was pulsatile. Pulses of P declined from 8.2 +/- 1.2/12 h (mean +/- SEM) before to 5.0 +/- 1.2 h after IL-1 beta treatment (P = 0.022), but increased to 10.2 +/- 4.3/12 h with cAMP. Interpulse interval increased significantly from 92 +/- 23 min (baseline) to 137 +/- 31 min (p = 0.025) after IL-1 beta treatment. Total P secreted decreased significantly from 2471 +/- 515 nmol/12 h (baseline) to 1480 +/- 167 nmoles/12 h during IL-1 beta and 788 +/- 85 nmoles/12 h after IL-1 beta (P = 0.015). P was immediately suppressed after starting IL-1 beta in 2 CL but declined only towards the end of treatment in the other 2 CL. PGF2 alpha secretion increased during IL-1 beta with a further increase after IL-1 beta, while P secretion was progressively inhibited. Therefore, IL-1 beta is luteolytic to the primate midluteal phase CL by inhibiting P while simultaneously stimulating PGF2 alpha secretion, demonstrating paracrine-autocrine interaction within the luteal tissue.

Objective: To present our current understanding of oxytocin and its receptors during pregnancy and parturition and their potential clinical applications., Data Sources: A MEDLINE search was conducted for pertinent articles from 1966 to October 1996 related to oxytocin and its receptor and their clinical implications during pregnancy and parturition. Review articles, book chapters, and published trials were also searched., Methods of Study Selection: Only references in English that were deemed relevant were used. When possible, human data and sometimes animal data pertinent to understanding the interaction of oxytocin and its receptors were selected., Tabulation, Integration, and Results: Oxytocin is synthesized in the hypothalamus and in many reproductive tissues during pregnancy, whereas the receptors are synthesized in reproductive tissues. The genes for oxytocin and its receptors are on chromosomes 20 and 3, respectively. Oxytocin and its receptors are regulated by sex steroids and by oxytocin itself. The paracrine and autocrine mechanisms regulating oxytocin and its receptor within the fetoplacental-uterine unit are central to the control of uterine contractions and parturition. Such current understanding provides the basis for appropriate oxytocin regimens to induce or augment labor, to inhibit preterm labor by blockade of oxytocin receptors, and to achieve cervical ripening., Conclusion: Advances in our knowledge of oxytocin and its receptor have provided rational and sound principles for current concepts about their role in parturition, the appropriate use of oxytocin to stimulate the pregnant uterus or ripen the cervix, and the use of oxytocin antagonist to inhibit uterine contractions and preterm labor.

The purpose of this study was to compare the CUE method for family planning with the Ovulation Detection Method for defining the fertile phase of the menstrual cycle. We evaluated 42 cycles from 10 women in Monterrey, Mexico, who were monitored by basal body temperatures, urinary LH, pelvic ultrasound, and the CUE monitor. The fertile phase of the cycle was adequately defined in all cycles using the CUE method, and in 35 cycles (83.3%) by the Ovulation Method. Using our protocol, the period of recommended abstinence with the CUE method is 9 days and with the Ovulation Method 11 days. The CUE method accurately defines the fertile phase of the menstrual cycle, thus improving the predictability of ovulation for women who use natural methods of birth control.

Objective: Our purpose was to determine and compare the efficacy and hormonal and metabolic effects of 1.25 mg with 2.5 mg of gestrinone given twice a week in the treatment of mild and moderate pelvic endometriosis., Study Design: A phase II, prospective, randomized, double-blind study involving 11 patients given gestrinone 1.25 mg (five patients) or 2.5 mg (six patients) orally twice a week for 24 weeks was performed. Revised American Fertility Society scores were determined by laparoscopy before and at the end of treatment. Serum hormone (free thyroxine, free testosterone, estradiol, progesterone, follicle-stimulating hormone, luteinizing hormone), sex hormone binding globulin, and lipid concentrations were measured before, throughout, and for 6 months after treatment. Quantitated computerized tomography of thoracic 12 through lumbar 4 vertebral bodies were determined before, at the end of, and 6 months after treatment., Results: Gestrinone 2.5 mg significantly reduced the endometriosis implant score from 10.3 +/- 2.8 to 3.8 +/- 0.8 (p = 0.05). Both doses significantly reduced serum progesterone and sex hormone binding globulin levels. Estradiol, free testosterone, free thyroxine, follicle-stimulating hormone, and luteinizing hormone levels were not significantly affected. Spinal bone increased significantly by 7.1% with 2.5 mg but lost significantly by 7.1% with 1.25 mg gestrinone; these changes had not reversed completely 6 months after stopping treatment., Conclusions: In mild to moderate pelvic endometriosis 2.5 mg of gestrinone twice a week was more effective and had a more positive effect on bone mass than did 1.25 mg of gestrinone.

Epidermal growth factor is known to have mitogenic effects in the ovary. To determine whether this effect is receptor-mediated, and whether the receptor number changes during the estrus cycle, in this study we have evaluated the total and occupied EGF receptor (EGFr) concentrations and receptor binding characteristics in adult rat ovaries collected at diestrus and early estrus. These represent stages before and after the pituitary LH/FSH surges of the estrus cycle. The 100,000 g plasma membrane fractions were isolated and EGFr concentrations evaluated with and without 1 mM EDTA treatment at pH 4.5 in order to release receptor-bound ligand and therefore assess the unoccupied and total receptor concentrations. EGF receptor affinity and number were analyzed by Scatchard analysis. No statistically significant difference between unoccupied and total receptor concentration in the diestrus phase ovaries was found. The percentage of occupied receptors (total-unoccupied) in diestrus membranes was 7.1%. In early estrus ovaries, a significant increase (P < 0.05) was observed in total receptor concentration when compared with the number of unoccupied receptors. The percentage of occupied receptors in early estrus membranes was 35.7%. Comparison between the ovaries from the two phases indicated an almost twofold increase in total EGF receptor number in early estrus membranes when compared with diestrus membranes. Furthermore, the percentage of occupancy between the two studied groups indicate a significant increase (P < 0.05) in the number of occupied receptors in early estrus when compared to diestrus. Thus, we have demonstrated that not only EGF receptor concentrations are modulated through the rat estrus cycle, but also the concentration of EGF-like substances bound to such receptors.

Using saturation binding assays and Scatchard analyses, we determined the concentrations and binding affinities of epidermal growth factor (EGF) receptors in human myometrium (n = 13) and decidua (n = 10) before and during labor and in placenta (n = 15), chorion (n = 17), and amnion (n = 17) before labor, during labor, and after vaginal delivery. Each tissue was individually assayed. In myometrium and chorion, EGF receptors increased significantly from 5.6 +/- 0.8 and 13.5 +/- 1.7 fmol/mg protein (mean +/- SEM) before labor to 11.1 +/- 2.8 and 26.7 +/- 3.0 fmol/mg protein, respectively, after the onset of labor (P < 0.05). In amnion, EGF receptors increased from 12.8 +/- 2.7 fmol/mg protein before labor to 33.0 +/- 2.3 fmol/mg protein during labor, but decreased significantly (5.9 +/- 1.2 fmol/mg protein) with vaginal delivery (P < 0.05). Decidual and placental concentrations of EGF receptors did not change significantly with labor. The binding affinity of EGF receptors in all tissues studied did not change significantly with labor, as reflected by their respective association and dissociation constants. Up-regulation of EGF receptors in myometrium, chorion, and amnion with spontaneous labor may enhance stimulation of prostanoid production and stimulate uterine activity.

Although oxytocin has been recognized as a product of the corpus luteum in numerous species, including nonhuman primate and women, for sometime, its precise role in luteal physiology has remained obscure. However, with the recent observations that the steroidogenic activity of the large and small cells is increased in the presence of LH when these cells are in intimate contact has led to the hypothesis that cell-to-cell communication must occur between these cells. Cell-to-cell communication is possible via several mechanisms, including paracrine/autocrine and intercellular crosstalk via gap junctions. Substantial morphological and immunohistological evidence using antibodies to gap-junction specific proteins, the connexins, indicates the presence of gap junctions in corpora lutea. Our recent studies indicate that oxytocin affects the expression of the gap-junction protein connexin-43 and that the gonadotropins are intimately involved in this action. The synthesis of oxytocin and the oxytocin receptor is influenced by the gonadotropins and locally produced prostaglandins. Oxytocin stimulates estradiol synthesis, which may affect the expression of the gap-junction protein connexin-43, allowing interaction between the large cells and small cells of the corpus luteum. With the ubiquitous presence of oxytocin and its receptor, and the presence of gap junctions in the corpora lutea of numerous species, it is concluded that oxytocin is involved in not only paracrine/autocrine interaction but also may be of significant importance in intercellular crosstalk in the corpus luteum.

Baboon corpora lutea (two each from the early, mid- and late luteal phases) were individually microretrodialyzed in vitro for 48 h, 12 h initial baseline, 12 h retrodialysis with OT (9 mU/h), 12 h without OT and 12 h with cAMP (5 mmol/h). Progesterone (P) was measured by a sensitive and specific radioimmunoassay in 10-min fractions of retrodialysates and analyzed for P peaks by PC-pulsar 3.0. Neither OT nor cAMP had any effect on the characteristics of P pulses. In early and late luteal phase CL, OT inhibited P secretion within 1 h of administration followed by increased P secretion late during OT perfusion. In midluteal phase, OT did not affect P secretion. In all CL, P secretion was sustained or further increased during the 12 h after stopping OT. cAMP also sustained baseline or stimulated P secretion. In contrast, OT either increased total P output/12 h (28 to 49% above baseline) with a further increase of 21% to 296% above baseline after stopping OT, or inhibited total P output by 4% to 13% percent with a further decline of 51% to 61% after stopping OT. Thus, while overall OT is luteotropic, its dual effect (initial inhibition followed by stimulation) suggests direct and indirect effects through paracrine-autocrine mechanisms.

We have previously shown that the protein connexin-43 which forms the connexons in gap junctions is present in the human corpus luteum. Abundant expression of connexin-43 is seen in the mid-luteal phase corpora lutea. Since the formation of gap junctions in a tissue requires the presence of adherens junctions formed by the cadherins, our aim in these studies was firstly to localize immunocytochemically E-cadherin and beta-catenin (a cytoplasmic protein associated with E-cadherin) in the human corpus luteum, and secondly to determine the concentrations of these proteins in the early, mid- and late luteal phase human corpora lutea. E-cadherin was localized to the periphery of luteal cells and was not detected in non-luteal tissue. beta-catenin was observed in the cytoplasm of the luteal cells. Abundant expression of E-cadherin was observed by Western analysis in the early luteal phase and the level of expression was significantly different from that observed in the mid- and late luteal phase corpora lutea. In contrast the concentrations of beta-catenin were higher in the mid-luteal phase compared to the early luteal phase. The differential expression of the cell adhesion molecule E-cadherin suggests that it may play a significant role in cell-to-cell communication in the corpus luteum, and in the cyclic development and demise of this tissue.

We have previously shown that gap junctions and gap junction-associated protein connexin 43 are present in the human and baboon corpus luteum. Abundant expression of connexin 43 is seen in the midluteal phase corpora lutea. Since the formation of gap junctions requires the presence of adherens junctions formed by the cadherins, our aim in these studies was 1) to immunocytochemically localize E-cadherin and the associated proteins, beta-catenin and gamma-catenin (plakoglobin), in the baboon corpus luteum; 2) to determine by Western analysis the levels of these proteins in early, mid-, and late luteal phase and atretic baboon corpora lutea; and 3) to examine whether or not cell-cell contact in cells in culture is disrupted by the addition of the antibody for E-cadherin. E-cadherin was localized to the peripheral cell membranes of luteal cells at all stages examined, except atretic corpora lutea, with the strongest immunoreactivity in the early luteal phase. Both beta-catenin and plakoglobin were localized in the cytoplasm of the luteal cells. Immunoreactivity for all three peptides was not observed in nonluteal tissue. By Western analysis, abundant expression of E-cadherin was observed in the early luteal phase, and the level of expression was significantly different from that observed in the mid- and late luteal phase corpora lutea. In contrast, the levels of beta-catenin and plakoglobin were higher in the midluteal phase compared to the early luteal phase. Addition of the E-cadherin antibody to early luteal phase cells in culture disrupted the cell-cell contacts between cells. Thus, cell adhesion involving E-cadherin may play a significant role in the cyclic development and demise of this tissue.

The identification of the cell junction-forming proteins connexin-43, a gap junction protein and E-cadherin, which is a component of adherent junctions, in the corpus luteum of both humans and baboons suggests that cell-cell interactions and metabolic cooperation must occur in this tissue. Occluding junctions are a third type of junction which form a physical barrier between cells. Thus, our aims in this study were firstly to examine the presence of the tight junction-associated protein zonula occludens-1 (ZO-1) by immunohistochemistry, and secondly to determine the concentrations of this protein in the early-, mid- and late luteal phase baboon corpora lutea of the menstrual cycle by a Western analysis. ZO-1 was localized mainly at the periphery of the luteal cells, and the intensity of immunoreactivity varied through the luteal phase, with comparatively stronger immunoreactivity in the mid-luteal phase than the early and late luteal phases. Atretic corpora lutea were devoid of activity. By Western analysis, bands of immunoreactivity were observed at 225 kDa, further confirming the presence of the protein. Maximum activity, as determined by densitometry, was observed in the mid-luteal phase. These data infer the presence of tight junctions in the corpus luteum and suggest that expression of the ZO-1 protein forming these junctions may be hormonally regulated within this tissue.

The ovary is a complex organ composed of cells of diverse lineages. Therefore, in this study we examined whether immunolocalization of various cytoskeletal, epithelial, immune-cell, and neural-associated proteins can differentiate various cells in the baboon and human ovaries. Surface epithelial cells exhibited immunoreactivity for cytokeratin and desmin, however, they did not immunostain for other epithelial markers such as carcinoembryonic antigen or epithelial membrane antigen. Smooth muscle actin was distributed apically whereas vimentin was localized basally in these cells. Ova exhibited strong immunoreactivity for S-100, Leu-M1, and neurofilament and did not show immunoreactivity for epithelial and cytoskeletal proteins. In antral follicles and theca cells, and after formation of corpus luteum, both granulosa and theca cells expressed immunoreactivity for vimentin. Cytokeratins were absent in the preantral and antral follicles. However, atresia and development of apoptosis was associated with expression of immunoreactive cytokeratins in atretic follicles. Development of corpus luteum led to major changes in the immunophenotype of follicular cells. The mere presence of immunoreactivity for cytokeratin and a strong immunoreactivity for desmin in the luteinized granulosa and not in the theca cells allowed discrimination of these cells from each other and from their ancestral cells. Proliferating cell nuclear antigen was present in various ovarian cells except for ovum. The distinct patterns of expression of cytoskeletal, epithelial, and neural-associated proteins in various cells of the ovary facilitates their identification and discrimination.

In the nonhuman primate and human corpora lutea, gap junctions have been identified by means of electron microscopy. Gap junctions are formed by connexons, which consist of a multigene family of tissue-specific connexins. In the ovarian follicle, the gap junction protein connexin-43 is present and hormonally regulated. However, there is little evidence indicating the type of connexin present in the corpus luteum. Therefore, the aim of this study was to demonstrate the presence of gap junctions by electron microscopy and the presence of connexin-43 and messenger ribonucleic acid (mRNA) for this protein. Using immunocytochemical procedures, we have shown the presence of connexin-43 in baboon and human midluteal phase corpora lutea and in the atretic corpora lutea of the baboon. The intensity of immunoreactivity was lower in atretic corpora lutea than in the midluteal phase corpora lutea. Western analysis indicates the presence of two bands at 43-45 kDa, and that the levels of connexin-43 protein are abundant in the midluteal phase. The two bands suggest the presence of the protein in a phosphorylated or a nonphosphorylated form. Ribonuclease protection assay suggests that the mRNA levels of connexin-43 remain constant throughout the luteal phase. mRNA for connexin-43 was not detectable in atretic corpora lutea. Thus, connexin-43 is one of the connexin family of proteins forming the connexon of gap junctions in the baboon and human corpus luteum. The expression of the protein may be hormonally regulated by locally produced factors, such as estradiol and progesterone. We suggest that gap junctional communication between the cells of the primate and human corpus luteum may be important in hormone synthesis and secretion and may be involved in the process of luteolysis through luteal cell apoptosis.

Oxytocin has been identified in both non-human primate and human corpora lutea of the menstrual cycle by RIA, immunocytochemistry and HPLC. Evidence for the transcription of the oxytocin gene in this tissue using PCR is available. Oxytocin receptors have been characterized by biochemical procedures. However, there is some debate as to whether the oxytocin identified in these tissues is biologically active and has a role in luteal function. In this study we have demonstrated that oxytocin isolated by gel chromatography of tissue extracts from the baboon and the human corpus luteum is biologically active as determined in a rat uterine bioassay. Since both oxytocin and its receptors are present in these tissues, it is suggested that oxytocin in the human and non-human primate corpora lutea has a functional role.

Objective: To determine the presence and compare the relative abundance of messenger RNA for epidermal growth factor receptor (EGFR) in baboon corpora lutea of different luteal ages., Design: Prospective controlled nonhuman primate study., Setting: Animal facility in an academic research institution., Participants: Six adult female baboons with well-defined regular menstrual cycles. Stage of the menstrual cycle was determined by observation and scoring of perineal turgescence. The day of maximal turgescence was referred to as the day of LH surge., Intervention: Ten corpora lutea were obtained by luteectomy during early (LH + 1 to 5 days, n = 3), midluteal (LH + 6 to 10 days, n = 3), and late (LH + 11 to 15 days, n = 4) luteal phases., Main Outcome Measure: Relative levels of messenger RNA for EGFR as determined by ribonuclease protection assay using RNA probe generated from complementary DNA for human EGFR., Results: Messenger RNA for EGFR is present in baboon corpora lutea with relative levels of 0.51 +/- 0.18 (mean +/- SEM) in the early, 0.43 +/- 0.17 in the midluteal, and 0.50 +/- 0.17 arbitrary units in the late luteal phase., Conclusion: Baboon corpus luteum is a site of EGFR production; the levels of its messenger RNA did not change appreciably throughout the luteal phase.

Objective: To determine changes in trabecular vertebral bone mass, serum E2, and serum calcitonin during and after therapy of pelvic endometriosis with depot leuprolide acetate (LA) or danazol., Design: Prospective, randomized, double-blind study., Setting: Academic university hospital and department of obstetrics and gynecology., Patients: Twelve women with symptomatic pelvic endometriosis diagnosed and staged by laparoscopy., Interventions: All patients received blinded treatment with either 3.75 mg JM depot LA given every month and daily placebo tablets (n = 6) or 800 mg oral danazol daily with a monthly placebo injection (n = 6) for 24 weeks., Main Outcome Measures: Quantitated computerized tomography of bone density of thoracic 12 to lumbar 4 vertebral bodies were determined before, at the end of 24 weeks of treatment, and 6 and 12 months after completing treatment. Gain or loss of bone mass was based against pretreatment levels. Serial serum levels of E2 and calcitonin before, throughout, and after therapy were compared with changes in bone mass., Results: Bone loss with LA was 14.0% +/- 0.5% (mean +/- SEM), recovering to a deficit of 4.2% +/- 3.8% and 3.3%, 6 and 12 months after stopping therapy. Danazol increased bone by 5.4% +/- 2.2%, with a further gain to 8.2% +/- 3.5% and 7.5%, 6 and 12 months after stopping treatment. Serum E2 levels usually were < 25 pg/mL (conversion factor to SI unit, 3.671) with LA but > 47.3 pg/mL with danazol. Calcitonin levels did not change significantly with either treatment., Conclusion: Depot LA produced marked sustained hypoestrogenemia and significant bone loss with incomplete recovery 1 year after stopping treatment. Danazol maintained normoestrogenemia and increased bone mass with the gain maintained even 1 year after stopping therapy.

Although oxytocin (OT) was identified in the human and primate corpus luteum (CL) over a decade ago, a definitive role for this peptide has not been elucidated. Several in vitro models have been utilized to examine the most obvious role for OT in luteal function, that of its effect on progesterone (P) production. Using dispersed cells in short term incubations, cultured cells and microdialysis procedures utilizing intact tissue, variable effects of OT on P production have been obtained. We therefore hypothesized that OT may have other role(s) in this tissue. The follicle cells remaining after a successful ovulation has occurred undergo rapid luteinization and the tissue is extensively remodeled to form the CL. At this time, in most species, two types of luteal cells have been identified based on their morphology, biochemistry and size. Both cell types produce P, however only one cell type responds to the long distance modulator LH. Since both cell types appear to be needed for the overall synthesis of P in adequate quantities required for the preparation of the endometrium "information trafficking" must occur between the two cell types. Our recent studies have shown the presence of gap junctions and connexin-43, E-cadherin, an adhesion molecule and ZO-1 protein associated with tight junctions in the baboon and human CL. The effect of OT on connexin-43 in the baboon CL has been examined.

The effects of insulin-like growth factor-1 (IGF-1) and cAMP on progesterone (P) secretion by CL of streptozotocin-induced-diabetic pregnant ewes were compared with the effects on normal pregnant animals. Two types of CL were identified in the ovaries removed on Days 126.6 +/- 2 of pregnancy. They were either large, reddish in color, and vascular (type A) or small and pale yellow (type B). Both types were found in diabetic and normal sheep. Each CL was divided in two and perfused in parallel for 14 h in an in vitro microdialysis-perifusion system. One half was used to evaluate basal P secretion and the effect of cAMP. The effect of IGF-1 and cAMP infusion was studied in the other half. During microdialysis, fractions were collected every 15 min, and P was determined by RIA. IGF-1 stimulated secretion of P in the large type A, normal and diabetic sheep CL in discrete pulses. The smaller CL (type B) from normal sheep produced comparatively higher levels of P in discrete pulses in the presence of IGF-1. However, the small CL from diabetic sheep showed no response to IGF-1 or cAMP, and P secretion was lower. Thus, it is probable that the large CL may be the "active" CL producing P and that IGF-1 stimulates pulsatile P secretion in such CL from both normal and diabetic pregnant sheep.

Pulsatility of serum progesterone (P) is usually ascribed to stimulation of the corpus luteum (CL) by pulsatile release of pituitary LH. We investigated P secretion by the primate CL by performing microretrodialysis on 6 fresh CL obtained at laparotomy from baboons (Papio anubis) with well defined menstrual cycles. Individually microdialyzed for 24-26 h with Dulbecco's Modified Eagle's Medium and Ham's F-12 enriched with HEPES buffer in a perifusion chamber, the retrodialyzed fluid was collected every 10 min and measured for P, estradiol, and 17 alpha-hydroxyprogesterone by specific and sensitive RIAs. The chronodynamics of hormone secretion were analyzed for pulse detection by PC-Pulsar 3.0. All 6 CL (2 each from early, LH +1 to +5; mid, LH +6 to +10; and late luteal phases, LH +11 to +15) demonstrated pulsatile secretion of P in vitro, with distinct and detectable peaks over the 24-26 h studied. The CL secreted 23-27 pulses of P in 24 h in early luteal, 8-20 pulses in midluteal, and 6-19 pulses in late luteal phases. Peak lengths were 23.8 +/- 18.5 to 35.7 +/- 17.1 min. Four CL gave interpeak intervals of 46-55 min, whereas two gave intervals of 136-137 min. Analysis of distribution of pulses against different interpulse intervals in individual CL and all CL together revealed a bell-shaped distribution, with the largest number of pulses seen at an interpulse interval of 21-40 min. Because of the low concentrations of estradiol and 17 alpha-hydroxyprogesterone retrodialyzed, a similar analysis of these data was not possible. Histological examination of the tissue at the termination of the experiment using hematoxylin and eosin and localization of 3 beta-hydroxysteroid dehydrogenase activity indicates that the steroidogenic potential of the tissue is minimally affected, although some morphological changes do occur. Our findings suggest autonomous pulsatile P secretion by the primate CL, indicating local control by and the presence of an intraluteal oscillator or pulse generator for P secretion.

Objective: To examine hCG receptor levels and binding kinetics in corpora lutea (CL) from tubal pregnancies., Design: Corpus luteum from tubal pregnancies, term normal pregnancies, and midluteal phase were obtained and compared for hCG binding., Setting: Department of Obstetrics and Gynecology, University Hospital., Interventions: Corpus luteum were obtained at elective cesarean section at term, tubal ligation, or surgery for ectopic pregnancy (EP)., Main Outcome Measures: Human chorionic gonadotropin receptor levels, dissociation and association constants using saturation binding assay, and Scatchard analysis., Results: Corpus luteum from late tubal pregnancies (> 7 weeks) and term intrauterine pregnancies had undetectable hCG binding. Corpus luteum from early tubal pregnancies (< 6 weeks) had significantly reduced hCG receptors with higher dissociation constants than from midluteal phase CL., Conclusions: Significant reduction of hCG receptors with accelerated binding dissociation may be the basis of CL dysfunction in some EPs.

Objective: To determine plasma levels of insulin-like growth factor-I (IGF-I), CA-125, estrone (E1), E2, and P in women with uterine leiomyomas compared with normal women., Design: Women with leiomyomas were compared with normal women (control)., Setting: University Department of Obstetrics and Gynecology., Patients: Fifty-one premenopausal women with uterine myomas > 14 weeks gestation and 30 normal fertile women (controls) were studied. Peripheral blood samples were obtained before myomectomy or hysterectomy and during the nonmenstruating phase in the controls., Main Outcome Measures: Plasma levels of E1, E2, P, CA-125, and IGF-I were determined by specific and sensitive RIAs and immunoradiometric assays., Results: Plasma IGF-I levels were 2,006 +/- 185 mU/mL (mean +/- SEM, n = 35) and 2,335 +/- 287 mU/mL (n = 16) in women with leiomyomas during the follicular and luteal phases, respectively, whereas the corresponding values for normal women were 1,702 +/- 120 (n = 30) and 1,774 +/- 239 mU/mL (n = 30). Similarly, plasma CA-125 levels were unchanged in women with leiomyomas (myomas: 18.8 +/- 2.4, 21.5 +/- 3.7 U/mL; normal: 15.9 +/- 1.5, 15.8 +/- 1.3 U/mL during follicular and luteal phases, respectively). Women with leiomyomas had plasma E1, E2, and P levels during the follicular phase (91.9 +/- 11.5 pg/mL; conversion factor to SI unit, 3.699; 94.6 +/- 19.0 pg/mL; conversion factor to SI unit, 3.671; and 1.5 +/- 0.4 ng/mL; conversion factor to SI unit, 3.180, respectively) and the luteal phase (105.8 +/- 11.2 pg/mL; conversion factor to SI unit, 3.699; 128.7 +/- 24.8 pg/mL; conversion factor to SI unit, 3.671; and 9.6 +/- 1.6 ng/mL; conversion factor to SI unit, 3.180) similar to normal women., Conclusion: Plasma levels of IGF-I, CA-125, E1, E2, and P are normal in women with leiomyomas.

Five postmenopausal women received single doses of a 0.675 mg estradiol hydroxypropyl-beta-cyclodextrin (estradiol-HP beta CD) sublingual tablet by the sublingual and oral route. A single dose of a 1 mg micronized estradiol tablet was given orally for comparison. Blood samples were obtained over 48 hours for measurement of estradiol, estrone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations. Sublingual administration produced faster and significantly higher peak estradiol concentrations than after oral administration of either estradiol-HP beta CD or micronized estradiol. The concentration-time area under the curve of estradiol after sublingual estradiol-HP beta CD was also significantly larger than after oral administration of either estradiol-HP beta CD or micronized estradiol, reflecting a larger estradiol bioavailability. The estradiol/estrone concentration ratio after sublingual estradiol-HP beta CD revealed a predominance of estradiol for the first 2 hours after the dose, followed by an estrone predominance. Both oral doses produced a predominant delivery of estrone to the systemic circulation. There was not difference in time-averaged LH suppression between the three phases. However, estradiol-HP beta CD sublingually produced greater FSH suppression than oral micronized estradiol.

To determine whether the effect of oxytocin (OT) on progesterone production in primate luteal tissue may be receptor-mediated, we used biochemical procedures to examine the CL of the baboon (Papio anubis) for the presence of OT receptors (OT-R). CL (n = 5) were obtained by luteectomy from the early (LH + 1-5 days), mid- (LH + 6-10 days), and late (LH + 10-15 days) luteal phases. Biopsies from the uterine fundus were also obtained at the same time. Total receptors were measured by incubating the membrane fractions (120,000 x g fraction) with increasing concentrations of [3H]oxytocin (0.08-1.6 nM) for 30 min at 22 degrees C with a protein concentration of 200 micrograms per tube. Nonspecific binding was evaluated by the addition of excess nonradioactive OT. The receptor-bound tritiated ligand was separated from the nonreceptor-bound ligand through use of polyethylene glycol. For the midluteal phase CL, the affinity Kd was 1.70 +/- 0.03 nmol/L and the mean receptor number (RT) was 122.6 +/- 8.3 fmol/mg protein. In comparison, myometrial tissue examined at the same phase of the cycle had a Kd of 1.3 +/- 0.1 nmol/L and an RT of 205.0 +/- 49.7 fmol/mg protein. Receptors were not detectable in the late luteal phase CL and were significantly lower in the early luteal phase CL (50.7 +/- 6.9 fmol/mg protein), with no difference in the Kd value. Competitive studies with structurally related and nonrelated peptides indicated the presence of specific receptors for OT in baboon CL.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: To determine the effect of melatonin on baboon corpus luteum (CL) cell progesterone (P) production., Design: Five baboon CL obtained during the midluteal phase by luteectomy were dissociated using collagenase, and incubations were performed (50,000 cells per plate) in quadruplicate for 3 hours at 37 degrees C with melatonin (0.001 to 1.0 ng/mL) (basal) or with melatonin and 10 IU of human chorionic gonadotropin (hCG) (hCG-stimulated). Total P was measured by a specific radioimmunoassay., Main Outcome Measures: Progesterone concentrations measured in the presence and absence of melatonin and hCG., Results: Melatonin (0.01 to 1.0 ng/mL) inhibited basal P production in all the CL (41.8 +/- 9.9 ng P without melatonin compared with 32.2 +/- 2.0 ng P, 28.4 +/- 2.1 ng with 0.01 and 1.0 ng/mL melatonin, respectively). Human chorionic gonadotropin-stimulated P production was significantly inhibited with as little as 0.01 ng of melatonin (150.8 +/- 11.4 ng with 10 IU hCG versus 120.3 +/- 6.4 ng with 10 IU hCG and 1.0 ng melatonin). The degree of inhibition in the hCG-stimulated cells was greater than in the nonstimulated cells. Melatonin at a concentration of 0.001 ng/mL did not affect P production in both stimulated and nonstimulated cells. Serotonin in similar concentrations had no effect on luteal cell P production., Conclusion: These findings indicate that melatonin exerts a suppressive effect on baboon dispersed luteal cell P production and thus may play a role in luteal function.

Objective: To determine the presence and binding characteristics of insulin-like growth factor (IGF) receptors in corpora lutea (CL) of spontaneous and clomiphene citrate (CC)-induced cycles and to identify any relationship between IGF receptors and cytosol progesterone (P) and 17 alpha-hydroxyprogesterone (17 alpha-OHP) levels., Design: Women undergoing bilateral tubal ligation were divided into two groups. One group received no medication (controls) and the other took 50 mg of CC. Midluteal phase CL were recovered at tubal ligation for hormone and receptor analysis., Setting: Patients were recruited from a university hospital setting., Patients: Eleven fertile women 26 to 37 years of age requesting bilateral tubal ligation were studied., Interventions: Four women were given 50 mg/d of CC from days 5 through 9 of study cycle. Seven women did not take any medication. Minilaparotomy bilateral tubal ligation and luteectomy were performed 7 to 9 days after midcycle urinary (LH) surge., Main Outcome Measures: Insulin-like growth factor receptor concentrations and binding characteristics and cytosol P and 17 alpha-OHP levels in individual CL., Results: Optimal binding for 125I-IGF-I with membrane fractions of homogenized CL was obtained with incubation at 4 degrees C for 16 hours. Specific binding (mean +/- SEM) was significantly higher in CC-treated (53.6% +/- 4.8%) than in control cycles (25.9% +/- 5.5%, P less than 0.001). Receptor concentrations were also significantly higher in CL from CC-induced (145.6 +/- 21.8 pmol/mg protein) than from control cycles (74.8 +/- 15.2 pmol/mg protein, P less than 0.02). Insulin-like growth factor receptor levels correlated with neither serum nor cytosol P and 17 alpha-OHP in CL from either cycles., Conclusion: Specific IGF-I receptors are present in human CL of the menstrual cycle with higher concentrations present in CC-induced cycles. Thus IGF may express its action on luteal function through its receptors in CL.

Midluteal phase endometrium was histologically dated with midcycle luteinizing hormone surge time in 29 cycles from 10 parous women during untreated cycles (control) and treatment with clomiphene citrate 50 mg and 150 mg daily on days 5 through 9. Integrated progesterone output for 7 days after luteinizing hormone surge calculated from the daily plasma progesterone levels was 66.6 +/- 9.8 ng/ml in the control group compared with 117.5 +/- 18.6 ng/ml for clomiphene citrate 50 mg treatment and 152.1 +/- 11 ng/ml for clomiphene citrate 150 mg treatment (p less than or equal to 0.05). Only one cycle (clomiphene citrate 150 mg) had an out-of-phase endometrium and a significantly reduced integrated progesterone output of 28 ng/ml. All other cycles showed synchronous endometrial maturation. We conclude that luteal insufficiency as a result of clomiphene citrate treatment in ovulatory women is infrequent and is more likely to be a result of functional outcome of a relative lack of luteal phase progesterone output.

Midluteal phase corpora lutea (CL) obtained from women induced with 50 mg (n = 5), 100 mg (n = 5), and 150 mg (n = 5) of clomiphene citrate (CC) were measured for luteinizing hormone/human chorionic gonadotropin (LH/hCG) concentrations and cytosol progesterone (P) and 17 alpha-hydroxyprogesterone (17-OHP) and compared with midluteal phase CL from eight normal women (controls). More CL (26) that were significantly heavier (2.0 +/- 0.3 g, [mean +/- SEM]) were obtained with CC than in controls (10). Clomiphene citrate treatment increased LH/hCG receptor concentrations and the dissociation constant significantly from 69 +/- 12 fmol/mg protein and 1.1 +/- 0.2 x 10(-10) M, respectively, in controls to 112 +/- 6 fmol/mg protein and 2.1 +/- 0.1 X 10(-10) M. Cytosol P and 17-OHP levels were not significantly increased. Cumulatively these cellular effects may be responsible for increasing serum P and responsiveness to hCG and for correcting luteal dysfunction.

Three-hour oral glucose tolerance tests were performed on days 5 and 25 of ovulatory menstrual cycles in 26 women. The women were divided into normal (n = 9) and premenstrual syndrome (PMS) (n = 17) categories. Ovulation was confirmed by basal body temperature records and plasma progesterone levels. There were no statistically significant changes in the plasma glucose or insulin levels between the two tests in either group. Except for a higher two-hour plasma insulin concentration on the day 5 test in normal women, no statistically significant carbohydrate differences were noted between the groups. The data suggest that alterations in carbohydrate metabolism are not important in PMS.

Cytosol progesterone (P) and 17 alpha-hydroxyprogesterone (17-OHP) levels and luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptors were measured in 27 corpora lutea and four corpora albicantia. Cytosol P concentrations were highest in corpora lutea (mean +/- SEM, 3.1 +/- 0.8 micrograms/g) during the midluteal phase (days 15 to 19) rather than the early (2.2 +/- 0.8 micrograms/g, days 20 to 25) and late luteal phases (1.8 +/- 0.8 micrograms/g, days 26 to 30). Cytosol 17-OHP concentrations also were 3.3 +/- 0.5, 4.3 +/- 0.6, and 3.3 +/- 1.0 micrograms/g in early, midluteal, and late luteal phases, respectively, and was significantly inversely correlated with occupied LH/hCG receptors in midluteal phase. Corpora albicantia had the lowest P (0.3 +/- 0.05 microgram/g) and 17-OHP (0.9 +/- 0.6 micrograms/g) concentrations. Cytosol P and 17-OHP may therefore reflect the balance between the luteal cell production and secretion, whereas the amount of occupied and unoccupied LH/hCG receptors may partially explain the relationship between LH and P secretion.

The usefulness of changes in salivary and vaginal electrical resistance (SER and VER) measurements for timing ovulation was evaluated in 15 cycles. A peak in mean SER was observed seven to eight days before the LH peak (five to nine days before the thermal nadir). The nadir of mean VER coincided with the day of maximum LH and was significantly correlated with the day of the thermal nadir. Use of SER peak and the rise of VER from its nadir in a protocol for timing insemination yielded correct timing in 93.3% (14/15) of cycles. These findings substantiate earlier reports indicating that there is a useful relationship between SER and VER trends and ovulation, which may be employed for accurate scheduling of inseminations and other procedures.

Plasma and salivary progesterone and estradiol were measured throughout nine menstrual cycles and before and after intramuscular injection of progesterone in four women. Mean +/- standard error of the mean (SE) salivary progesterone increased significantly from 238.7 +/- 14.3 pg/ml in the proliferative phase to 475.3 +/- 39.8 pg/ml in the secretory phase (p less than 0.001). There was a highly significant correlation between plasma and salivary progesterone levels throughout the menstrual cycle (r = 0.5841, p = 0.001). The ratio of plasma to salivary progesterone was 6.4 during the proliferative phase and increased to 26.7 during the secretory phase. Free unbound progesterone as determined by equilibrium dialysis gave a mean +/- SE level of 126.8 +/- 6.9 pg/ml during the proliferative phase and increased significantly to 196.8 +/- 18.8 pg/ml during the secretory phase (p less than 0.001). The corresponding levels in the plasma were 88.5 +/- 11.2 pg/ml, which increased significantly to 332.2 +/- 39.2 pg/ml (p less than 0.001). Free progesterone constituted 53.7% and 41.4% of salivary progesterone during the proliferative and secretory phases, respectively, whereas the corresponding percentages in the plasma were 5.8% and 2.6%. Both plasma and salivary progesterone levels increased in a dose-dependent manner after an intramuscular injection of progesterone, with peak levels being attained from 2 to 3 hours after the injection. Salivary estradiol levels were 5 to 18 and 8 to 35 pg/ml in the proliferative and secretory phases, respectively, but showed no correlation with plasma estradiol levels. The findings are discussed in relationship to the origin of salivary progesterone and the potential use of it as an index of ovulation.

The mechanisms controlling luteal function may involve factors that are produced both within the corpus luteum and outside the ovary. The process of luteal control appears to involve a series of molecular species, proteins, peptides, steroids and prostaglandins. Each of these factors may act independently or in concert modifying the actions of one another. The effect of GnRH on luteal function has not been completely examined and thus its significance is unclear. The neurohypophyseal peptides, oxytocin and arginine vasopressin, in combination with LH, prolactin, oestrogens and prostaglandins may play an important regulatory role on the corpus luteum.

Thirty-one normal women were studied daily in 41 cycles. Venous blood samples were taken for measurements of luteinizing hormone (LH), estradiol (E2), and progesterone (P), and vaginal examinations were done to obtain cervical mucus and vaginal fluid. The specific activity of guaiacol peroxidase (GP), extracted from cervicovaginal secretions with 0.5 M CaCl2, was determined in the vaginal samples. In the follicular phase, from day -7 to day 0 (the LH +1 day, when ovulation presumably occurred), there was a strong negative correlation between GP and the rising E2 (r = -0.94). On days 1 to 10 after ovulation, there was a strong positive correlation between GP and P (r = 0.84). In nine ovulatory cycles in which P levels did not exceed 8 ng/ml on any day, indicating possible luteal phase inadequacy, there were significantly lower GP levels than in another 32 ovulatory cycles with higher P (P = 0.04). These results suggest that (1) at midcycle, E2 seems to "down-regulate" the GP specific activity; and (2) in the luteal phase, serum P levels parallel those of GP activity, even in the presence of high luteal E2. GP activity profiles during the menstrual cycle can be used to define the fertile period, may prove useful in diagnosing pregnancy, and may be a simple, convenient test for an inadequate corpus luteum.

Naloxone (10 mg) was given intravenously to seven postmenopausal women not receiving hormone treatment and to six postmenopausal women receiving Premarin-Provera treatment during the Premarin phase and also during the Premarin-Provera phase of therapy. Baseline estrone and estradiol levels (mean +/- SEM) were significantly lower in the group not receiving hormones (46.0 +/- 5.2 pg/ml and 28.4 +/- 3.1 pg/ml, respectively) than in the group in the Premarin phase of therapy (154 +/- 14 pg/ml and 79 +/- 13 pg/ml) and the group in the Premarin-Provera phase (135.1 +/- 8.3 pg/ml and 57.5 +/- 3.0 pg/ml) (p less than 0.005). Follicle-stimulating hormone, luteinizing hormone, and prolactin levels were 118.7 +/- 5.3 mIU/ml, 118.7 +/- 9.5 mIU/ml, and 9.2 +/- 0.7 ng/ml, respectively, with no significant change after naloxone administration in untreated women. With hormone therapy the basal follicle-stimulating hormone and luteinizing hormone levels decreased significantly while basal plasma estrone and estradiol increased significantly. In both the group in the Premarin phase of therapy and the group in the Premarin-Provera phase, luteinizing hormone levels increased significantly at 30 (135% +/- 10%, 144% +/- 8%), 45 (150% +/- 12%, 133% +/- 11%), 60 (149% +/- 15%, 128% +/- 11%), and 90 (139% +/- 15%, 132% +/- 13%) minutes after naloxone administration (p less than 0.01 to p less than 0.001). Follicle-stimulating hormone levels did not change significantly whereas prolactin levels showed a trend toward a decrease. These findings indicate that opioid inhibition of gonadotropins is reduced in postmenopausal women but increased with Premarin-Provera treatment. The effect of sex steroid on the opioid system in the postmenopausal women differs from that in the premenopausal women.