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Although progesterone plays an essential role in ovulation and the luteiniziation of the primate follicle, the expression of cellular components required for progesterone synthesis and their control is not well defined. This study was designed to determine the time course and gonadotrophin versus steroid regulation of the transcription of genes involved in progesterone synthesis in peri-ovulatory follicles. Granulosa cells or whole ovaries were obtained from macaques undergoing controlled ovarian stimulation either before (0 h) or up to 36 h following the administration of an ovulatory human chorionic gonadotrophin (HCG) bolus with or without a 3β-hydroxysteroid dehydrogenase (3β-HSD) inhibitor, with or without a non-metabolizable progestin. Granulosa cell concentrations of low density lipoprotein receptor (LDL-R) and steroidogenic acute regulatory protein (StAR) mRNA increased transiently 12 h following HCG administration (P < 0.05) at which time steroid depletion tended to reduce StAR mRNA (P = 0.06). At 36 h post-HCG progesterone suppressed the LDL-R mRNA levels (P < 0.05). P450 side-chain cleavage (P450scc) mRNA decreased in a time-dependent fashion up to 24 h, whereas 3β-HSD mRNA increased within 12 h of HCG administration (P < 0.05) in a steroid-independent manner. Whole ovarian 17α-hydroxylase (P450c17) and granulosa cell P450 aromatase (P450arom) mRNA declined in a time-dependent fashion; by 36 h after HCG administration, steroid depletion increased P450arom mRNA, although progestin replacement did not return aromatase to control values (P < 0.05). These data demonstrate diverse patterns of steroidogenic enzyme expression that generally reflect the conversion of the macaque peri-ovulatory follicle from an oestrogen to progesterone producing gland. Although mRNAs associated with progesterone synthesis and metabolism are primarily regulated by gonadotrophins, cholesterol uptake and utilization may be modulated locally by steroids... [ABSTRACT FROM AUTHOR]

The role of endothelial cell-specific growth factors in the vascularization of the primate peri-ovulatory follicle was examined. Experiments were designed firstly to detect expression of vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) in granulosa cells and secondly, to determine whether gonadotrophins and/or steroids regulate their expression during the peri-ovulatory interval. Granulosa cells and follicular fluid were collected from rhesus macaques undergoing ovarian stimulation before (0 h), 12, or 36 h after a bolus of ovulatory human chorionic gonadotrophin (HCG), with or without steroid ablation and progestin replacement. VEGF, Ang-1 and Ang-2 mRNA were all detected prior to the ovulatory stimulus. Whereas follicular fluid VEGF concentrations increased 6-fold (P < 0.05) between 0 and 12 h, VEGF mRNA values were unchanged and were unaffected by steroid ablation. Ang-1 mRNA decreased from 0 to 12 h (P < 0.05), followed by a 30-fold increase (P < 0.05) at 36 h, while Ang-2 mRNA values were unchanged between 0, 12 and 36 h. Steroid ablation decreased (P < 0.05) Ang-1 mRNA at 36 h, and Ang-2 mRNA at 12 h, while only Ang-1 was restored by progestin replacement. These data suggest a dynamic expression of vascular-specific growth factors in a gonadotrophin-dependent, steroid-independent (VEGF) or steroid-dependent (Ang-1) manner in granulosa cells of peri-ovulatory follicles of primates. [ABSTRACT FROM AUTHOR]

Examines the dynamic expression of vascular endothelial growth factor and angiopoietin-1 and -2 in the macaque corpus luteum during the menstrual cycle. Role of the endothelial cell-specific factors in the development, maintenance and regression of the primate corpus luteum; Angiogenic factor expression in the corpus luteum.