Bovine theca and granulosa cells interact to promote androgen production

Pieces of theca interna or follicle wall (theca interna + attached granulosa cells), obtained from bovine preovulatory follicles prior to the surge of luteinizing hormone (LH) and cultured for 3 days, secreted androstenedione. Luteinizing hormone, but not follicle-stimulating hormone (FSH), increased production of androstenedione 3 to 4-fold. In both the presence and absence of LH, follicle wall preparations secreted about 4-fold more androstenedione than did equivalent amounts of theca interna tissue. Isolated granulosa cells produced only negligible quantities of androstenedione, which suggests that they may contribute to the greater production of androstenedione by follicle wall by supplying progestin precursor to the theca cells. The addition of pregnenolone or progesterone to isolated theca interna increased the secretion of androstenedione, but pregnenolone was by far the more effective precursor. This suggested that the delta 5 (delta 5) pathway is the preferred pathway for androstenedione synthesis by bovine theca cells and that granulosa cells might supply progestin precursor in the form of pregnenolone. Follicle wall and granulosa cell cultures secreted 2 and 7 times more pregnenolone, respectively, than did theca cultures. Luteinizing hormone, but not FSH, increased production of pregnenolone by the follicle wall, whereas the gonadotropins had no effect on secretion by either granulosa or theca cells. Since exogenous testosterone enhanced the production of pregnenolone by granulosa cells, thecal androgen (which is stimulated by LH) may increase the ability of granulosa cells to make pregnenolone and explain the stimulatory effect of LH on pregnenolone secretion by follicle wall.(ABSTRACT TRUNCATED AT 250 WORDS)