Development of gonadotrophin-binding sites in the immature rat ovary

There was a temporal relationship between ovarian development and the sites to which 125I-labelled gonadotrophins became bound. Labelled human LH and FSH bound uniformly to 5- and 15-day-old ovaries. At 21 days, heavy FSH and light LH binding was observed over the granulosa cells increased at Day 33 and again at Day 38. Quantitative determination by gamma-ray spectrophotometry of binding to ovarian sections showed that LH binding gradually increased with advancing age, but FSH binding remained relatively constant between Days 5 and 33 with a significant increase between Days 33 and 38.