Androgens promote insulin-like growth factor-I and insulin-like growth factor-I receptor gene expression in the primate ovary

It has recently been shown that androgens increase the growth of immature f ollicles in the primate ovary. In the present study the effect of androgens on ovarian insulinlike growth factor I(IGF-I) and IGF-I receptor gene expr ession was investigated. The study groups included five follicular phase, p lacebo-treated controls, and four testosterone- and three dihydrotestostero ne (DHT)-treated rhesus monkeys. The treatment period was 5 days. Both test osterone and DHT treatment resulted in significant, 3-4-fold increases in I GF-I mRNA concentration in granulosa, thecal and interstitial compartments. Likewise, both androgens induced significant increases in the amount of IG F-I receptor mRNA, most notably in thecal cells and less markedly in granul osa and interstitium (P < 0.05). These changes in amounts of IGF system mRN A were documented in growing follicles up to the small antral (less than or equal to 1 mm diameter) stage. Larger follicles were too few in number for significant comparisons. By contrast, amounts of ovarian insulin receptor mRNA were not appreciably altered by androgen treatment. These data suggest that IGP-I and its cognate receptor may mediate androgen-induced ovarian f ollicular and thecal-interstitial growth.