Occupied and unoccupied FSH receptors in follicles of cyclic, hypophysectomized or hypophysectomized/gonadotropin-treated hamsters.
Occupied and unoccupied FSH receptors were measured in follicles from intact cyclic hamsters or in animals hypophysectomized on day 1 (= estrus) which were untreated or given ovine FSH on day 1 plus LH on days 1-4 or FHS and LH plus 1 mg progesterone on days 1-4. Intact hamsters, from days 2-4, the number of occupied and unoccupied FSH receptors and receptor affinity was unchanged in antral follicles. For the untreated hypophysectomized hamsters, serum FSH was undetectable beyond day 3 but receptor affinity increased on day 2 and the number of occupied FSH receptors was still very high on day 4. Thus, in the hypophysectomized untreated hamster the ovary is not hormonally deprived - at least up until day 4. Treatment of the hypophysectomized hamsters with FSH-LH restored all follicular values of levels of intact hamsters on days 2 and 3. On day 4, although serum FSH was undetectable since day 3 the number of occupied FSH receptors was 70% of control values. The FSH-LH regimen developed by day 4 large antral follicles in the hypophysectomized hamsters. Collectively, the experiments demonstrate that in intact hamsters as a result of the prolonged peak of serum FSH on day 1 FSH binds avidly to receptors in granulosa cells and persists until day 4. Thus, the follicles in the hypophysectomized groups develop in response to exogenous LH but with hamster FSH still present, bound to granulosa cells.
D000818:Animals; D006224:Cricetinae; D004971:Estrus; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism / Q000494:pharmacology*; D007016:Hypophysectomy; D007700:Kinetics; D007986:Luteinizing Hormone / Q000494:pharmacology*; D006080:Ovarian Follicle / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D011962:Receptors, FSH; D012756:Sheep
D011956:Receptors, Cell Surface; D011962:Receptors, FSH; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone