Steroid synthesis by ovarian follicles in response to LH and PGF2alpha

Ovarian follicles isolated from bovine ovaries at the 16th and 17th days of the estrous cycle were minced, pooled, and incubated in Krebs-Ringer bicarbonate buffer at 37degrees for 2 hr. Samples were analyzed for testosterone, estrogens, and progesterone by radioimmunoassays. Incubation alone failed to cause an increase in testosterone (12.1 vs 29.3 ng/g of tissue; P is greater than 0.05). Additions of 5 mug/ml of bovine LH or prostaglandin F2alpha caused increases in testosterone synthesis to 125.0 (Pis less than 0.01) and 103 ng/g (P is less than 0.01). Estradiol synthesis was also stimulated by LH (P is less than 0.01). However, stimulation due to addition of PGF2alpha (5.1 to 15 ng/g) was not significant (P is greater than 0.05). PGF2alpha also caused a slight but nonsignificant increase in estrone secretion. Incubation failed to increase the progesterone concentration (623 vs 774 ng/g of tissue; P is greater than 0.05). There was no increase in progesterone synthesis due to addition of either LH or PGF2alpha (P is greater than 0.05). The results show that bovine follicles produce much more testosterone than estrogen and that both LH and PGF2alpha significantly stimulate testosterone synthesis in bovine follicular tissue without increasing net progesterone biosynthesis.