ONTOGENESIS, DISTRIBUTION AND RELATIVE SENSITIVITY OF HCG RECEPTORS TO HCG AND LH IN GOAT OVARIES

The binding of [125I]hCG [125I-human chorionic gonadotropin] to immature and mature follicles and corpora lutea of goat ovaries was studied. The hormone is bound maximally by corpora lutea, although mature follicles also exhibit some binding. Immature follicles are practically devoid of receptors for this hormone. In the corpus luteum receptors for the hormone are present in thecal and luteal cells. Autoradiographic studies show the location of the bound radioactivity grains primarily along the plasma membranes of these cells, although some radioactivity grains were also seen in the cytoplasm of luteal but not thecal cells. On a mole to mole basis, hCG displaced [125I]hCG from binding to receptors on corpus luteum better than hLH [human luteinizing hormone] and o[ovine]LH.