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Antiprogestins (APs) inhibit estradiol (E(2))-stimulated endometrial growth in women and nonhuman primates, but the mechanism of this "antiestrogenic" action is unknown. Here, we report that APs up-regulate endometrial androgen receptor (AR) in both women and macaques, an effect that might play a role in the antiproliferative effects of APs on the primate endometrium. In addition, because there are discrepancies in the literature on the regulation and localization of AR in the primate endometrium, we used both in situ hybridization and immunocytochemistry to evaluate hormonal influences on endometrial AR in women and macaques. In ovariectomized macaques, the following treatments were given for 4 weeks each: E(2) alone, E(2) + progesterone (P), E(2) + mifepristone (RU 486), and E(2) + P + RU 486. In women, samples were obtained during the normal menstrual cycle and after treatment with either RU 486 for 30 days at 2 mg/day, or after a single oral administration of 200 mg RU 486 on cycle day LH + 2. In macaques, E(2) significantly increased AR expression above vehicle controls; E(2) + RU 486 increased binding further; E(2) + P decreased AR binding; and E(2) + P + RU 486 treatment caused an intermediate elevation in AR binding. In macaques treated with E(2) alone, stromal AR staining was predominant, and P treatment suppressed that staining. E(2) + RU 486 or E(2) + P + RU 486 treatment produced a striking up-regulation of glandular epithelial AR staining and enhanced the stromal AR signal. In situ hybridization analyses confirmed the immunocytochemistry data. Similar induction of glandular AR staining and enhanced stromal AR staining were obtained in macaques treated with ZK 137 316 and ZK 230 211. During the natural cycle in women, stromal AR staining predominated and was greater in the proliferative than the late secretory phase. RU 486 treatment of women up-regulated glandular epithelial AR staining after either daily treatment for 30 days with 2 mg/day or after a single oral dose of 200 mg. In summary, endometrial AR was highest in the stroma during the human proliferative phase (or during E(2) treatment in macaques) and lowest during the late secretory phase in women (or after E(2) + P treatment in macaques). In both species, RU 486 induced AR expression in the glands and enhanced AR expression in stromal cells. Because androgens can antagonize E(2) action, enhanced endometrial AR expression induced by APs could play a role in the antiproliferative, "antiestrogenic" effects of APs in primates.

The objective of this study was to detect and characterize a secreted oviduct-specific glycoprotein (OGP) in the rhesus macaque (Macaca mulatta) and to compare the characteristics of this OGP to those previously characterized in baboons and women. Oviducts were obtained from untreated ovariectomized rhesus and from ovariectomized rhesus either treated with estradiol (E2) for 14 days or treated sequentially with E2 for 14 days and then with E2 plus progesterone (P4) for an additional 14 days. Segments of oviducts were either fixed for morphological analysis, cultured for OGP synthesis and release, or frozen for RNA analysis. The proteins present in the culture media were separated by one-dimensional SDS-PAGE, and OGP was detected on Western blots using polyclonal antibodies generated against the reduced form of baboon OGP or a 17-amino acid segment of the baboon core protein. Cross-reacting antigens were present in the 120-kDa region, identical to what was observed for baboon and human OGP. Indirect immunogold localization of OGP on thin sections demonstrated specific clustering of gold particles over the apical secretory granules of the secretory cells of the oviductal epithelium. A cDNA was generated using RT-PCR and 5' and 3' rapid amplification of cDNA ends (RACE), and sequenced. The total transcript was 2237 nucleotides in length plus a poly(A) tail. The largest open reading frame was 624 amino acids, which would produce a protein of 69.3 kDa. The nucleotide sequence was more than 95% identical to the nucleotide sequences of baboon and human OGP. Northern blots revealed a single message at 2.4 kilobases (kb) in oviduct samples obtained from E2-treated rhesus. This message was absent in oviducts obtained from untreated ovariectomized and from sequential E2 plus P4-treated rhesus macaques. In summary, the rhesus oviduct synthesizes and secretes an OGP in the presence of E2 that is immunologically and structurally similar to the baboon and human OGP. The presence of a highly homologous glycoprotein in several primates suggests a similar function for OGP in the reproductive process.

Rhesus monkeys are useful models in which to examine the hormonal regulation of endometrial matrix metalloproteinases (MMP) and to evaluate the role of MMP in uterine bleeding. Artificial 28 day menstrual cycles can be induced in ovariectomized monkeys by inserting an oestradiol implant for 2 weeks, then inserting a progesterone implant for 2 weeks, and then, with the oestradiol implant remaining in place, removing and reinserting the progesterone implant at 2 week intervals. To examine MMP during menses, we established such cycles and removed uteri by hysterectomy at closely spaced intervals before, during and after menses, as well as at later time points. Some samples were also obtained during menses induced by the withdrawal of both progesterone and oestradiol. We examined mRNA of the following MMP by Northern blotting: matrilysin, stromelysin-1, stromelysin-2, stromelysin-3 and the tissue inhibitor of MMP TIMP-1. The expression of these MMP mRNA increased substantially by 2-3 days after progesterone withdrawal, whether or not oestradiol was maintained. The expression of some of the MMP (stromelysins-1 and -2) returned very rapidly to baseline levels by 5 days after progesterone withdrawal, while the expression of others (matrilysin, stromelysin-3 and TIMP-1) declined more slowly, reaching a baseline level by 10 days after progesterone withdrawal, with little or no further decline after progesterone concentrations rose during the induced luteal phase. Immunocytochemical studies showed that matrilysin was expressed primarily in the glands of the upper functionalis. In other work with the rhesus monkey model, we used a s.c. endometrial autograft technique in which pieces of endometrium were autotransplanted to the abdominal skin. During menses in the grafts, matrilysin was expressed in the glands of the grafts similar to the glands in the eutopic endometrium. Endometrial autografts can serve as a useful model for the study of MMP in uterine bleeding.

Two experiments were conducted to determine how RU486 affected oestradiol action in the non-human primate female reproductive tract. In the first experiment, spayed rhesus monkeys were first treated with a sequential regimen of oestradiol and progesterone to cause regression and deciliation in the oviduct and progestational development in the endometrium. The ability of oestradiol to stimulate oviductal differentiation and endometrial regeneration in the presence of RU486, progesterone, and progesterone plus RU486 was then tested. RU486 was found to block the ability of oestradiol to increase endometrial growth but did not prevent oestradiol-dependent oviductal differentiation. Also, in the endometrium but not the oviduct, RU486 action differed from simple progesterone withdrawal by causing stromal compaction and glandular apoptosis. In the second experiment, spayed monkeys were first treated with oestradiol for 2 weeks to produce a fully differentiated, ciliated-secretory oviduct and an hypertrophied, proliferative endometrium. The ability of oestradiol to maintain these conditions in oviduct and endometrium during treatment with RU486, progesterone, and progesterone plus RU486 was then tested. It was found that RU486 suppressed the ability of oestradiol to maintain the endometrium in a hypertrophied state but not its ability to maintain the oviduct in a fully ciliated-secretory state. As before, RU486 induced extensive glandular apoptosis and stromal compaction in the endometrium, but not the oviduct. These endometrial effects appeared to be due to a combination of a decrease in proliferation, an increase in epithelial cell death by apoptosis, an increase in stromal compaction and a concomitant decrease in interstitial fluid content, all of which led to a decrease in endometrial wet weight and thickness. These effects of RU486 on oestradiol action were similar in the presence and absence of progesterone and were therefore separate and distinct from the classical antiprogestin effects of RU486. Because RU486 did not inhibit the ability of oestradiol to either stimulate or maintain oviductal differentiation or wet weight, these results suggest that the endometrium is much more sensitive to the anti-proliferative effects of RU486 than the oviducts.

Recently, we reported that in rhesus monkeys, RU 486 treatment could inhibit the ability of estradiol (E2) to stimulate endometrial regeneration without inhibiting E2-dependent oviductal regeneration. In that work, RU 486 had been administered at the end of an artificial luteal phase when the oviducts were regressed, the endometrium was in a late secretory state, and estrogen and progestin receptors (ER and PR, respectively) were at minimal levels in both organs. In the current work, we administered RU 486 after 2 weeks of estrogen priming when the oviducts were fully differentiated, the endometrium was in a proliferative state, and ER and PR levels were maximal. Our goal was to determine whether the degree to which RU 486 inhibited E2 action in either organ varied depending on their initial state. Spayed rhesus monkeys were primed with E2 for 2 weeks and then treated in four different ways for an additional 2 weeks as follows: I) E2; II) E2 plus P; III) E2, P, and RU 486; and IV) E2 plus RU 486. Menstruation was not induced by any of the four treatments. In group I, continuous treatment with E2 maintained a typical proliferative endometrium with abundant Ki-67-positive cells, low levels of apoptosis, and elevated ER and PR; the oviducts were also maintained in a fully ciliated-secretory state. In group II, P induced a typical progestational secretory state in the endometrium, with few proliferating (Ki-67-positive) epithelial cells, undetectable apoptosis, and decreased ER and PR; as expected, the oviducts were fully regressed, with few Ki-67-positive or ciliated epithelial cells and low levels of ER and PR. In the endometria of monkeys treated with RU 486 and E2, either with (group III) or without (group IV) P, the effects of E2 on wet weight, thickness, and epithelial proliferation were more dramatically inhibited than in our previous study. However, the oviducts of the RU 486-treated animals had remained in a hypertrophied, fully ciliated-secretory state as in our previous study, with elevated ER and nuclear PR, although epithelial proliferation was suppressed. The degree to which RU 486 can inhibit estrogen-dependent growth in the endometrium can apparently be affected by the state of differentiation and/or steroid receptor level at the time the antiprogestin treatment is begun, but this effect is not evident in the oviduct, which shows only modest antiproliferative effects of the RU 486 treatment.

We previously reported that RU486 can reverse progesterone (P)-induced suppression of the estrogen receptor (ER) in the uterus of pregnant rhesus monkeys, but we did not determine whether estrogen (E) could act through its receptor in the presence of P and RU486. To pursue this question, we treated spayed rhesus monkeys with various hormonal regimens and evaluated the effects of E in the oviduct and endometrium, with and without RU486 treatment, on ER and progestin receptor (PR) levels, morphology, apoptosis, and degree of proliferation. The latter was assessed immunocytochemically with a monoclonal antibody (Ki-67) against a nuclear antigen present only in proliferating cells. Animals were treated for 2 weeks with 17 beta-estradiol (E2) and then for 2 weeks with E2 plus P to produce a regressed oviduct and a secretory endometrium. The animals were then treated for 2 more weeks with four different treatments, as follows: I) E2, P, and vehicle; II) E2 and vehicle; III) E2, P, and RU486; and IV) E2 and RU486 (n = 4 each). In group I, menstruation did not occur, and the endometrium exhibited stromal cell enlargement, extensive development of the spiral arteries, few Ki-67-positive cells, and low levels of ER and PR. Oviducts in group I remained regressed, Ki-67-positive epithelial cells were few, and levels of ER and PR were low. In contrast, in groups II, III, and IV, the oviducts had responded to E2 and were fully ciliated and secretory, with elevated levels of ER and nuclear PR. All animals in these three groups menstruated and then regenerated their endometrium. The regenerated endometria expressed elevations in ER, nuclear PR, and epithelial Ki-67 index. However, the endometria of RU486-treated monkeys in groups III and IV had significantly more epithelial cell death by apoptosis, increased stromal cell compaction, and fewer Ki-67-positive stromal cells than in the E2 controls (group II). In group IV, RU486 caused a significant decrease in endometrial weight. Thus, RU486 blocked P action and allowed E2 to act in a normal fashion in the oviduct and endometrium on several end points, but it also had antiproliferative effects that opposed E2 action, especially in the endometrium.

We obtained the testes, ductuli efferentes, and epididymides from adult rhesus and cynomolgus macaques and examined these tissues for estrogen receptors (ER) with immunocytochemistry (ICC) and a sucrose gradient assay. Both techniques employed monoclonal antibodies prepared against ER, and both showed that high concentrations of ER were present OFFy in the ductuli efferentes. Moreover, all specific staining was confined to the nuclei of the nonciliated, absorptive epithelial cells. The quantity of salt-extractable ER in the ductuli efferentes (834 +/- 161 [SEM] fmol/mg DNA [n = 8]) did not differ significantly from the amounts measured with the identical assay in oviducts and endometrium of estrogenized female macaques. Testes and epididymides of macaques had no specific staining by ICC and barely detectable amounts by biochemical analysis (7 +/- 4 [n = 3], 8 +/- 2 [n = 5], 33 +/- 16 [n = 3], and 6 +/- 3 [n = 8] fmol/mg DNA for testis and caput, corpus, and cauda epididymis, respectively). The functional significance of the high levels of ER in the ductuli efferentes of macaques remains to be determined.

We compared the morphology of ovaries from fetal rhesus monkeys at two different stages of gestation with the ability of ovarian tissue to synthesize androgens and estrogens in vitro. Ovaries collected between 80 and 104 days of gestation contained single-layered primordial follicles but no multilayered or antral follicles. Within these ovaries we found theca-like interstitial cells which contained abundant smooth endoplasmic reticulum and lipid droplets. These ovaries produced androstenedione and dehydropiandrosterone (but not estradiol) in vitro in the absence of exogenous substrates. Ovaries collected between Days 124 and 153 of gestation, however, contained numerous, well-developed multilayered and antral follicles. The ultrastructural characteristics of the thecal and granulosa cell layers were similar to those of adult ovarian follicles. These ovaries synthesized large amounts of androstenedione, dehydroepiandrosterone, and estradiol in vitro. Identity of the estradiol was confirmed by incubating homogenates of late gestation ovaries with [14C]progesterone, by isolation of estradiol and formation of its derivative, and by recrystallization to constant specific activity. In vitro cyclic AMP synthesis was stimulated by Pergonal (luteinizing hormone [LH] + follicle stimulating hormone [FSH] ) only in ovaries which contained multilayered and antral follicles, an indication that fetal ovaries contain gonadotropin receptors during late stages of development. These data indicate that fetal ovaries of rhesus monkeys attain the capacity for de novo estrogen biosynthesis and to respond to gonadotropins during late gestation, when multilayered and antral follicles have developed.