TY - JOUR
AU1 - Poretsky, Leonid
AU2 - Bhargava, Girija
AU3 - Levitan, Eve
AB - Hyperandrogenism observed in a variety of hyperinsulinemic states is thought to be due to an effect of insulin mediated through the type I insulin-like growth factor (IGF) receptors. These receptors, however, have not yet been demonstrated in normal human ovarian cells capable of androgen production. We now report the presence of type I IGF receptors in membrane preparations of human ovarian stroma. The ovarian stromal tissue was obtained from women undergoing indicated oophorectomy. Stromal plasma membranes were prepared. Specific <sup>125</sup>I-IGF-I binding was 6.6 ± 0.2%/100 µg protein. The affinity constant estimated by Scatchard analysis was 4.6 × 10”<sup>9</sup>M. 50% inhibition of <sup>125</sup>I-IGF-1 binding was observed at 5 ng/ml of IGF-1. Specificity of the <sup>125</sup>I-IGF-I-binding sites was confirmed by analogue specificity studies and in experiments utilizing monoclonal antibody to the IGF-I receptor, α-IR-3. IGF-II and insulin competed with <sup>125</sup>I-IGF-I for the binding sites, but with an affinity significantly lower than that of IGF-I: 50% inhibition was observed at approximately 60 ng/ml of IGF-II or insulin. α-IR-3, a monoclonal antibody with high specificity for the type I IGF receptor, effectively inhibited <sup>125</sup>I-IGF-I binding in a dose-dependent manner, confirming that the <sup>125</sup>IGF-I binding was indeed to the type I IGF receptor. We conclude that type I IGF receptors are present in human ovarian stroma. These receptors may mediate effects of insulin on the ovary in hyperinsulinemic insulin-resistant states.
TI - Type I Insulin-Like Growth Factor Receptors in Human Ovarian Stroma
JF - Hormone Research in Paediatrics
DO - 10.1159/000181441
DA - 1990-01-01
UR - https://www.deepdyve.com/lp/karger/type-i-insulin-like-growth-factor-receptors-in-human-ovarian-stroma-emEiezPyMI
SP - 22
EP - 26
VL - 33
IS - 1
DP - DeepDyve
ER -