Steroid Synthesis by Ovarian Follicles in Response to LH and PGF 2 α

Abstract

Summary

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 37° 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 > 0.05). Additions of 5 μg/ml of bovine LH or prostaglandin F₂α caused increases in testosterone synthesis to 125.0 (P < 0.01) and 103 ng/g (P < 0.01). Estradiol synthesis was also stimulated by LH (P < 0.01). However, stimulation due to addition of PGF₂α (5.1 to 15 ng/g) was not significant (P > 0.05). PGF₂α 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 > 0.05). There was no increase in progesterone synthesis due to addition of either LH or PGF₂α (P > 0.05). The results show that bovine follicles produce much more testosterone than estrogen and that both LH and PGF₂α significantly stimulate testosterone synthesis in bovine follicular tissue without increasing net progesterone biosynthesis.