Factors affecting the secretory dynamics of 1 alpha-hydroxycorticosterone in the dogfish, Scyliorhinus canicula

The secretory dynamics (plasma concentrations, metabolic clearance rates (MCR), and blood production rates (BPR] of 1 alpha-hydroxycorticosterone (1 alpha OH-B) were examined in Scyliorhinus canicula under a number of experimental conditions. Both hypophysectomy and injections of dexamethasone significantly reduced the plasma concentrations of 1 alpha OH-B, although significant, measurable amounts remained. In hypophysectomized animals MCR increased and BPR decreased. Intravenous administration of Squalus and mammalian adrenocorticotrophic hormone (ACTH) preparations, homologous renal extracts, and mammalian angiotensin II all increased plasma concentrations of 1 alpha OH-B; apart from Squalus ACTH these materials increased BPR of 1 alpha OH-B and both ACTH preparations reduced the MCR. In none of the experimental groups were there major changes in plasma osmolality or in sodium, potassium, magnesium, chloride, calcium, or urea concentrations. It is concluded that the secretory patterns of 1 alpha OH-B are significantly influenced by renal materials in addition to hypophysial ACTH.