THE INFLUENCE OF FSH, LH AND TESTOSTERONE ON STEROIDSECRETION BY 2 SUBPOPULATIONS OF PORCINE GRANULOSA-CELLS

The first objective of this research was to define the capacity of two types granulosa cells (mural MGs and antral AGc) to secrete estradiol (E(2)) in the presence of an androgen substrate (testosterone). The s econd objective was to identify the synergism between gonadotropic hor mones such as LH and FSH and testosterone (T) as measured by E(2) secr etion by MGc and AGc. MGc were separated from AGc by filtration throug h a 32.5 mu m nylon filter. In the first experiment, control cultures were grown in M199 medium supplemented with 10% calf serum while the o ther cultures were supplemented with either T alone at a concentration of 1 x 10(-7) M or with 1.0 x 10(-3) M, 0.5 x 10(-3) M, or 0.1 x 10(- 3) M aromatase inhibitor CGS 16949A plus T. In the second experiment, cultures were enriched either with 1 x 10(-7) M T or with 100 ng LH pl us T or 100 ng FSH plus T. After 24 hours of cultivation all cultures were terminated and the media were frozen at -20 degrees C for further steroid analysis. Basal E(2) secretion was always higher in MGc than in AGc. Adding testosterone to the culture medium decreased E(2) secre tion by MGc but significantly increased E(2) secretion by AGc. LH in t he absence of T was without effect on E(2) secretion by both Gc types. FSH alone stimulated E(2) secretion by MGc and decreased E(2) secreti on by AGc. Synergistic action of FSH and LH with T on E(2) secretion b y both types of granulosa cells was observed. These findings provide t he basis for further analysis of the differences in aromatizing abilit y of the two subpopulations of Gc during follicular development.