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The midcycle gonadotropin surge promotes vascular endothelial growth factor-A (VEGF-A) production by granulosa cells in the ovulatory follicle, but it is unclear whether primary regulators of VEGF secretion in other tissues, including hypoxia and growth factors, are also important in the ovary. To address these issues, granulosa cells were collected from rhesus monkeys during controlled ovarian stimulation either before (i.e., nonluteinized granulosa cells, NLGCs) or 27 hours after (i.e., luteinized granulosa cells, LGCs) administration of an ovulatory bolus of hCG, and cultured in fibronectin-coated wells containing a chemically defined media. When NLGCs were transferred to various O2environments (20%, 5%, or 0% O2) or media containing 100 mM CoCl2, LH (100 ng/ml)-stimulated progesterone (P4) levels were markedly (P< 0.05) suppressed by 0% O2or CoCl2. VEGF concentrations also declined (P< 0.05) in control, CoCl2, and CoCl2+ LH groups in 0% O2, although CoCl2modestly increased (75% above control; P< 0.05) VEGF levels in 20% and 5% O2. When NLGCs were cultured in the presence of recombinant human insulin-like growth factor (IGF)-1, IGF-2, or insulin, there was a dose-dependent increase (P< 0.05) in VEGF levels on Day 1 of culture. Whereas optimal doses of IGF-1 or IGF-2 (50 ng/ml), hCG (100 ng/ml), and IGF plus hCG stimulated VEGF levels on Day 1, only the combination of IGF-1 or IGF-2 plus hCG increased VEGF above controls and sustained levels through Day 3 of culture. The synergistic effects of IGF and hCG were also evident in P4levels, and were not due to changes in DNA content between treatment groups. LGCs produced much higher levels of P4and VEGF, but the responses to different O2concentrations and insulin-related factors were qualitatively similar to those of NLGCs. These results suggest that hypoxia is not a primary regulator of VEGF production in primate granulosa cells. However, IGFs may act in concert with the gonadotropin surge to promote VEGF secretion in the ovulatory, luteinizing follicle.

BACKGROUND: Administration of low doses of an antiprogestin to rhesus monkeys permits ovarian/menstrual cyclicity, suppresses endometrial proliferation and prevents pregnancy without adverse or toxic side‐effects after 5–6 months of daily treatment. The purpose of this study was to test the reversibility with respect to restoration of fertility after 1 year of low‐dose antiprogestin treatment. METHODS: This experiment included a daily 1 year vehicle‐ or antiprogestin‐treatment interval followed by a 9 month post‐treatment interval for adult, female rhesus monkeys (n = 5/group) of proven fertility and exhibiting regular menstrual cycles. Co‐habitation occurred with a male of proven fertility and vaginal swabs were taken to identify the presence of sperm during the treatment (antiprogestin females) and post‐treatment intervals (vehicle and antiprogestin females). RESULTS: Mating and vaginal sperm were evident in all antiprogestin females during, and, in both groups, after treatment. Based on ultrasonography, none of the antiprogestin‐treated females became pregnant during the treatment interval. However, upon cessation of treatment, pregnancy rates were similar between antiprogestin‐treated (3/5) relative to vehicle‐treated (4/5) females with live, healthy infants born in both groups. There were no differences between groups in fetal measurements, gestation lengths, live birth rates and infant weights. CONCLUSIONS: The reversal of the anti‐fertility effects of chronic, low‐dose antiprogestin treatment supports the clinical feasibility of potent and selective antiprogestins as potential contraceptives for women.

Detailed analysis of the action of prostaglandins (PGs) on the corpus luteum in primate species is very limited. In this study we examined the response of the adenylate cyclase system to PGs in homogenates prepared from the corpus luteum of rhesus monkeys at midluteal phase of the menstrual cycle. The conversion of [α32P] ATP to [32P] cyclic AMP (cAMP) was assessed in the absence (control activity; 50 μM GTP) and presence of various concentrations of seven PGs and arachiodonic acid, either alone or in combination with 250 nM hCG. Cyclic AMP production increased up to three-fold in the presence of PGD2, PGE2, PGI2or PGF2α; however PGA2, PGB2, 13,14-dihydro-15-keto PGE2and arachidonic acid alone did not alter cAMP levels. In dose-response studies, adenylate cyclase was 10 and 100-fold more sensitive to PGD2(Vmaxat 1 × 10−5M) than to PGE2or to PGI2and PGF2α, respectively. Activity in the presence of hCG plus either PGD2, PGE2, PGI2or PGF2αdid not differ from that for hCG (or the PG) alone. In contrast, addition of PGA2or arachidonate inhibited (p‹0.05) hCG-stimulated cAMP production by 50 and 100 percent. We conclude that the gonadotropin-sensitive adenylate cyclase of the macaque corpus leteum is also modulated by several PGs. These factors may either mimic (e.g., PGD2, PGE2, PGI2) or suppress (PGA2)_ gonodotropin-stimulated cAMP production and possibly cAMP-mediated events in luteal cells.

Both follicle stimulating hormone (FSH) and luteinizing hormone (LH) are proposed requirements for follicular growth and steroidogenesis; however, the role of LH in primate folliculogenesis is unclear. Follicular stimulation by recombinant human FSH (n = 5) with and without recombinant LH (1: 1; n = 6) following 90 days of gonadotrophin-releasing hormone (GnRH) antagonist (Antide) treatment in macaques was evaluated. Human chorionic gonadotrophin (HCG) was administered when six follicles >4 mm were observed. Oocytes were aspirated 27 h later and inseminated in vitro. Chronic Antide reduced serum oestradiol and bioactive LH to concentrations observed in hypophysectomized rhesus monkeys. Multiple follicular growth required a longer interval following recombinant FSH (12 ± 1 days) than recombinant FSH + recombinant LH (9 ± 0.2 days), but the total number of follicles/animal did not differ between groups. The day prior to HCG, oestradiol concentrations were 4-fold less following recombinant FSH compared to recombinant FSH + recombinant LH. With recombinant FSH, more oocytes completed meiosis to metaphase II(51%) and fertilized (89 ± 5%) relative to recombinant FSH + recombinant LH (12 and 52 ± 11% respectively). Follicular growth and maturation in LH-deficient macaques occurred with FSH alone. Thus, LH is not required for folliculogenesis in primates. Higher fertilization rates following follicular stimulation with FSH alone suggest that the presence of LH with FSH (1: 1) during the pre-ovulatory interval impairs gametogenic events in the periovulatory period.