Follicle Stimulating Hormone Stimulation of 125 l-Human Chorionic Gonadotropin Binding in Porcine Granulosa Cell Cultures 1

Abstract

Summary

In order to see if FSH acts directly upon the granulosa cell to stimulate hCG binding, granulosa cells harvested from small 1-2 mm porcine follicles were grown in 250 ml flasks in chemically defined media containing 0.05 μg/ml highly purified human FSH for 2, 4, and 6 days. The defined medium consisted of culture medium 199 plus 0.4% bovine serum albumin, 0.2% lactalbumin hydrolysate and 10 munit/ml insulin. The cultures were harvested by scraping with a rubber policeman and incubated with 0.1 μg/ml ¹³¹I- or ¹²⁵I-hCG. Binding expressed as cpm/culture or per mg protein yielded similar results. In five separate experiments addition of FSH stimulated hCG binding two- to fourfold above control cultures. In a typical experiment after 2 days of culture, the specific binding of control cultures to hCG was 962 ± 45 cpm/culture (x ± SE; n = 3) and the binding in cultures grown in the presence of 0.05 μg/ml FSH was 3933 ± 1787 (n = 3; P < 0.01). Granulosa cells harvested from large (8-12 mm) follicles grown under similar conditions bound 29,669 ± 948 cpm/culture (n = 4). These data demonstrate that FSH may have a direct stimulatory role upon induction of granulosa cell LH-hCG receptors in vitro.