The purpose of the proposed research is to determine the molecular basis for regulation of luteinizing hormone (LH) receptor synthesis and expression of LH receptor function using, as a model system, the inducton of LH receptors by follicle-stimulating hormone (FSH) in primary cultures of porcine ovarian granulosa cells. The specific aims are 1) to document the molecular events required for FSH-induced appearance of LH receptors, e.g. transcription, translation, glycosylation; 2) to correlate temporally the appearance of LH receptors with expression of function, i.e. LH-stimulation of adenylate cyclase activity, in an effort to determine whether receptor "processing" might occur subsequent to receptor incorporation into the cell surface membrane; 3) to explore the existence of post-incorporation processing of the receptor using sedimentation, isoelectric focusing, lectin specificity, and electrophoretic properties to resolve putative "pre-receptor" from "receptor" forms; 4) to quantitatively evaluate what fraction of the LH receptors which appear in response to FSH results from de novo synthesis using density gradient centrifugation to isolate "old" from "new" receptors rendered denser by incorporation of 15N, 13C, 2H amino acids; and 5) to learn whether recovery of LH receptors following autologous desensitization to LH occurs via the same synthetic route as FSH-induction of LH receptor appearance. Sensitivity to all hormones is dependent, in part, on the density and functional efficacy of their specific receptors. These studies in the ovarian granulosa cell model system will outline the molecular basis for FSH-induced differentation of the granulosa cell critical for ovulation and luteinization, and simultaneously clarify whether the regulation of receptor density in the process of differentation is similar or not to the regulation of receptor density in desensitized states.