The broad goal of this project is to understand the steps involved in the hormonal control of steroidogenesis. This includes the metabolic events that follow stimulation of trophic hormone receptors in the Leydig cells, luteal cell and adrenal fasciculata cells by gonadotropins and ACTH. Studies were focused on the interaction of hormones with their receptor and on analysis of coupling mechanism between receptor occupancy and androgen, progesterone or corticosterone synthesis. The two major questions examined are: (1) the relationship of receptor occupancy to cyclic AMP and protein kinase activation during acute dose related increases in steroid production and trophic actions of gonadotropin; and (2) the sequence of events which lead to stimulation of enzymes of the steroidogenic cells. This program has relevance to reproductive endocrinology and for the understanding of the mechanism of action of peptide hormones upon target cells.