Follicle-Stimulating Hormone and Luteinizing Hormone Receptors on Porcine Granulosa Cells during Follicular Maturation: An Autoradiographic Study

Summary

The autoradiogram prepared from porcine ovaries after incubating for 1 hour at 37 ^°C with either ¹²⁵I-labelled FSH or LH revealed that FSH bound to granulosa cells while LH bound to thecal cells. Although the granulosa cells of small, medium and large follicles were labelled with FSH, the decrease in grains over granulosa cells was observed during follicular maturation. In contrast, the granulosa cells of small and medium follicles showed only slight labelling with LH, while the granulosa cells of large follicles showed heavy labelling. The present study also indicated that granulosa cells collected from small follicles bound much more ¹²⁵I-labelled FSH per cell than did cells from medium or large follicles, and granulosa cells harvested from large follicles bound much more ¹²⁵I-labelled LH per cell than did cells from small or medium follicles. The competition studies with unlabelled hormones revealed that porcine granulosa cells had specific receptors for FSH and LH. The results of the present study suggest that a marked change in the binding of FSH and LH to the granulosa cells from the three follicle types might play a role in follicular growth and maturation.