title: Apparent positive cooperativity of ACTH action on adrenocortical cells: the effect of hormone degradation.
abstract: The ability of adrenocortical cells to degrade ACTH1--39 and [125I]ACTH has been assessed under various conditions. Under conditions leading to increased hormone degradation there was an elevation of both the ED50 and the value of the Hill coefficient derived from concentration-effect curves for ACTH-stimulated steroidogenesis. Such degradative mechanisms offer a simple explanation for tha apparent positive cooperativity proposed by others for ACTH-receptor-adenylate cyclase interactions.
mesh_terms: D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism*; D000305:Adrenal Cortex Hormones / Q000096:biosynthesis; D000311:Adrenal Glands / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D066298:In Vitro Techniques; D007700:Kinetics; D051381:Rats
chemical_list: D000305:Adrenal Cortex Hormones; D000324:Adrenocorticotropic Hormone