Effects of insulin on steroidogenesis in cultured porcine ovarian theca.

The effects of insulin on porcine thecal steroidogenesis were examined in long-term cultures of hyaluronidase-collagenase dispersed thecal cells. The thecal cultures made significant amounts of progesterone (P) and androstenedione (delta 4 A). Testosterone, dihydrotestosterone, estrone, and estradiol could not be detected in the media. Luteinizing hormone (LH) alone significantly increased P and delta 4 A accumulation. Insulin alone increased P accumulation on days 2 to 4 of culture. Insulin alone did not stimulate delta 4 A accumulation. Insulin plus LH resulted in a significantly greater accumulation of P and delta 4 A than LH alone. These results suggest that insulin may be a regulator of ovarian thecal steroidogenesis.