FSH and LH up-regulate epidermal growth factor receptors in rat granulosa cells

Epidermal growth factor (EGF) modulates ovarian folliculogenesis and steroidogenesis and its binding sites have been demonstrated in the ovary. We investigated the localization of EGF-binding sites in the rat ovary, and the effects of FSH and LH on EGF binding to cultured granulosa cells. Autoradiographic localization of 125 I-labelled mouse EGF-binding sites was demonstrated in the granulosa and luteal cells. Displacement study and Scatchard analysis showed that a single class of specific binding sites for 125 I-labelled mouse EGF was present in the granulosa cells, obtained from the ovaries of immature rats treated with diethylstilboesterol. The number of binding sites and the apparent dissociation constant were 4336 binding sites/cell and 3-42 pmol/l respectively