Effect of Follicular Fluid and Oestradiol on the Luteinization of Rat Granulosa Cells in Vitro

Abstract

Summary. The

Inhibitory effect of follicular fluid on RNA synthesis of rat granulosa cells in vitro

“…The small but not significant reduction of inhibition observed with the oestrogen-free follicular fluid may have been due to a slight inactivation of the treated follicular fluid. The oestrogens of follicular fluid strongly stimulate the secretion of proges¬ terone by rat granulosa cells in vitro, although they do not influence its inhibitory effect on morpho¬ logical luteinization of the cells (Bernard, 1975). This finding, and the data of the present study, lend support to the hypothesis that luteinization may involve regulation of at least two processes, namely progesterone synthesis and morphological changes.…”

“…Bernard (1975) showed that pig follicular fluid prevents morphological differentiation of rat granulosa cells in vitro, but does not alter their progesterone secretion. To investigate further the presence and nature of a 'luteinization inhibiting factor' in follicular fluid we compared the incorporation of [3H]uridine into the total RNA by rat granulosa cells after incubation in either serum or bovine follicular fluid.…”

“…Follicular fluid was collected at the slaughterhouse from cow follicles 3-15 mm in diameter, centrifuged and kept at -30°C until used. Half of this fluid and dialysed fetal calf serum (GIBCO) were incubated at 37°C in dextran-charcoal buffer for 2 h to eliminate all the oestrogens (unpublished data) and most of the other steroids present (Bernard, 1975). As described by Bernard (1975), granu¬ losa cells were removed from immature Wistar rats 51 h after injection of 30 i.u.…”

“…Half of this fluid and dialysed fetal calf serum (GIBCO) were incubated at 37°C in dextran-charcoal buffer for 2 h to eliminate all the oestrogens (unpublished data) and most of the other steroids present (Bernard, 1975). As described by Bernard (1975), granu¬ losa cells were removed from immature Wistar rats 51 h after injection of 30 i.u. PMSG, but just before the critical period of endogenous LH release (Strauss & Meyer, 1966).…”

“…The cells were placed in equal quantities in plastic scintillation vials, for maintenance in culture without mitotic divisions (Channing & Ledwitz-Rigby, 1975), and incubated for 22 h in 1 ml medium, at 37°C in an atmosphere of 5 % C02 in air. The medium consisted of 50 % of the'control medium' (90% TC 199; 10% dialysed fetal calf serum; antibiotics: see Bernard, 1975) and of 50% of either oestrogen-free dialysed fetal calf serum or untreated ('total') or oestrogen-free follicular fluid. In three experiments ovine LH (activity : 2-26 x NIH-LH-S1) was added to all three media to give a final concentration of 1 pg/ml.…”