FOLLICLE-STIMULATING-HORMONE AND LUTEINIZING-HORMONE CHORIONIC-GONADOTROPIN STIMULATION OF VASCULAR ENDOTHELIAL GROWTH-FACTOR PRODUCTION BYMACAQUE GRANULOSA-CELLS FROM PREOVULATORY AND PERIOVULATORY FOLLICLES

Granulosa cells in the ovulatory follicle express messenger ribonuclei c acid encoding vascular endothelial growth factor (VEGF), an agent th at may mediate the neovascularization of the developing corpus luteum, but it is not known whether luteinizing granulosa cells synthesize an d secrete VEGF during the periovulatory interval. Studies were designe d to evaluate the effects of an in vivo gonadotropin surge on VEGF pro duction by macaque granulosa cells (study 1) and to test the hypothesi s that gonadotropins act directly on granulosa cells to regulate VEGF production (study 2). Monkeys received a regimen of exogenous gonadotr opins to promote the development of multiple preovulatory follicles. N onluteinized granulosa cells (i.e. preovulatory; NLGC) and luteinized granulosa cells (i.e. periovulatory; LGC) were aspirated from follicle s before and 27 h after an ovulatory gonadotropin bolus, respectively. Cells were either incubated for 24 h in medium with or without 100 ng /mL hCG (study 1) or cultured for 6 days in medium with or without 100 ng/mL hCG or 0.1, 1, 10, and 100 ng/mL of recombinant human LH (r-hLH ) or r-hFSH (study 2). Culture medium was assayed for VEGF and progest erone. In study 1, LGC produced 8-fold greater levels of VEGF than NLG C (899 +/- 471 vs. 111 +/- 26 pg/mL, mean SEM; P < 0.05). In vitro tre atment with hCG increased (P < 0.05) VEGF production by NLGC to levels that were not different from the LGC incubated under control conditio ns. In vivo bolus doses of r-hCG (100 and 1000 IU) and r-hFSH (2500 IU ) were equally effective in elevating granulosa cell VEGF production. In study 2, in vitro treatment with r-hFSH, r-hLH, and hCG markedly in creased (P < 0.05) VEGF and progesterone production by the NLGC in a d ose- and time-dependent manner. By comparison, the three gonadotropins (100 ng/mL dose) only modestly increased VEGF and progesterone produc tion by LGC. These experiments demonstrate a novel role for the midcyc le surge of gonadotropin (LH/CG or FSH) in primates to promote VEGF pr oduction by granulosa cells in the periovulatory follicle. Further, th e data demonstrate that FSH-like as well as LH-like gonadotropins dire ctly stimulate VEGF synthesis by granulosa cells.