Insulin-like growth factor (IGF) binding protein-1 is an antigonadotropin: Evidence that optimal follicle-stimulating hormone action in ovarian granulosa cells is contingent upon amplification by endogenously-derived IGFs

Implicit in the antigonadotropic property of IGFBPs is the presumption that they sequester endogenously-generated IGFs thereby diminishing their access to cognate cell surface receptors and hence their cellular hormonal action. This communication examines this concept and the relevance of endogenous IGF to FSH action.