VASCULAR ENDOTHELIAL GROWTH-FACTOR PRODUCTION BY HUMAN LUTEINIZED GRANULOSA-CELLS IN-VITRO

Vascular endothelial growth factor/vascular permeability factor (VEGF/ VPF) originating from the follicle or corpus luteum may be a physiolog ical regulator of ovulation and neovascularization of luteinizing tiss ue, as well as a pathological factor in the development of ovarian hyp erstimulation syndrome (OHSS). The objective of this study was to quan tify VEGF production by human luteinized granulosa cells in vitro and to determine if gonadotrophin stimulates VEGF production directly and/ or indirectly via enhanced synthesis of progesterone, In study 1, lute inized granulosa cells collected from women undergoing ovarian stimula tion for in-vitro fertilization were cultured in the presence and abse nce of human chorionic gonadotrophin (HCG; 100 ng/ml) and/or low densi ty lipoprotein (LDL; 100 mu g protein/ml), In study 2, the progesteron e synthesis inhibitor trilostane (250 ng/ml) and/or a progesterone rec eptor antagonist ZK137.316 (3.2 mu M) were also added, Medium was harv ested on days 1, 3, 5, 7 and 9 of culture and assayed for VEGF and pro gesterone, Results of study 1 were divided into two categories based o n control concentrations of VEGF on day I:'low producers' (n = 6; < 75 0 pg VEGF/ml) and 'high producers' (n = 5; > 1000 pg VEGF/ml; P < 0.01 ), VEGF concentrations in cultures of both low and high producers incr eased (P < 0.01) from day 1 to maximal values on day 3, then steadily declined through to day 9, Chronic exposure to LDL or HCG increased (P < 0.05) VEGF concentrations in cultures of low producers by day 3 and day 5 respectively, In contrast, LDL did not alter VEGF concentration s in cultures of high producers and HCG did not increase VEGF concentr ations until day 7, Nevertheless, acute exposure to HCG beginning on d ay 7 increased (P < 0.05) VEGF concentrations 3-fold in cultures of lo w or high producers, In study 2, trilostane treatment decreased (P < 0 .05) progesterone concentrations by 91% on day 1 of culture but had no effect on VEGF concentrations on any day, ZK137.316 alone or with tri lostane did not affect VEGF synthesis, These results suggest that VEGF production by luteinized granulosa cells is enhanced by gonadotrophin (HCG) independent of gonadotrophin-stimulated progesterone synthesis, These data are consistent with the hypothesis that the exacerbation o f OHSS in early pregnancy is mediated by the CG stimulation of luteal VEGF production.