Human granulosa cells in vitro: characteristics of growth, morphology and influence of some cytokines on steroidogenesis.

Granulosa cells (GCs) were characterised morphologically by light and electron microscopy. The steroidogenic capability of GCs in vitro was estimated by radioimmunoassay (RIA): oestradiol (E2), progesterone (P) and androstenedione (A) secreted into the culture medium were measured. The influence of several culture media and anchorage of the cell either to plastic vessels (monolayer) or to collagen fibrils (in gel) were studied. As the various culture media were assayed with regard to their suitability for IVF, it was found that Ham's F10 is quite satisfactory (in agreement with other observations on embryo cultures). A chemically defined medium BM 86 was found to be inadequate. In addition to the two cell types which are known, a third cell type which can perform efficient aromatisation (E2 production) in vitro is characterised here. The influence of cytokines/growth factors (GF) like insulin-like GF (IGF-1), epidermal GF (EGF), platelet-derived GF (PDGF) and fibroblast GF (FGF) on steroidogenesis was tested either alone or with human chorionic gonadotrophin (hCG). Except for oestradiol (E2) from early GCs, hCG generally stimulated progesterone (P) and E2 secretion. EGF by itself enhanced the secretion of P but not of E2. EGF did not affect hCG stimulation of P, but reduced that of E2. In contrast, in pre-ovulatory GCs IGF-I reduced the stimulatory effect of hCG on both E2 and P. In early GCs IGF-I potentiated hCG stimulation of P. In early GCs, neither hCG nor IGF-I nor a combination of IGF-I with hCG had any effect on E2 production.