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

Abstract

The secretory dynamics (plasma concentrations, metabolic clearance rates (MCR), and blood production rates (BPR) of 1α-hydroxycorticosterone (1αOH-N) were examined in Scyliorhinus canicula under a number of experimental conditions. Both hypophysectomy and injections of dexamethasone significantly reduced the plasma concentrations of 1αOH-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 1αOH-B; apart from Squalus ACTH these materials increased BPR of 1αOH-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 1αOH-B are significantly influenced by renal materials in addition to hypophysial ACTH.