Regulation of human ovarian insulin receptors in vivo

Insulin participates in regulating ovarian function in normal and in pathological states. This effect of insulin may be mediated by ovarian insulin receptors. We have previously characterized human ovarian insulin receptors and began to examine their regulation in vitro. The present study examines regulation of human ovarian insulin receptors in vivo. Stromal ovarian tissue was obtained from 21 women during an indicated surgical procedure. Ten women were premenopausal and 11 were postmenopausal. Specific 125I-insulin binding to stromal ovarian fragments ranged from 2.5% to 7.3%/mg protein. 125I-insulin binding to stromal fragments correlated positively with 125I-insulin binding to circulating leucocytes (r = .57; P less than .01). When postmenopausal and premenopausal women were analyzed separately, this relationship persisted in postmenopausal women (r = .70; P less than .05), but not premenopausal women. 125I-insulin binding to stromal ovarian fragments correlated negatively with age (r = -.63; P = .005). 125I-insulin binding to stromal ovarian fragments tended to correlate negatively with plasma insulin levels in postmenopausal women (r = -.67; P = .06), but not in premenopausal women. Plasma insulin levels correlated negatively with serum SHBG (r = -.62; P = .003). The percent free testosterone levels correlated positively with plasma insulin levels in premenopausal women (r = .95; P = .0001), but not in postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)