Acidosis Activation of the Pituitary-Adrenal-Renal Glutaminase I Axis

Publisher Website
Google Scholar
Abstract
Previous studies demonstrated that the adrenal glands were necessary for acidosis activation of the mitochondrial glutaminase I pathway. These studies were undertaken to determine if corticosterone levels are elevated in acidotic rats and if so, whetehr acidosis stimulates the adrenal glands directly or via the pituitary-adrenal axis. Metabolic acidosis induced by NH4Cl, either acute or chronic, increased corticosterone levels 100-130% in intact rats. Acute metabolic acidosis did not activate the mitochondrial pathway in adrenalectomized rats; corticosterone levels were not elevated in hypophysectomized rats, nor did activation of the mitochondrial pathway occur in response to acidosis. Acidosis does not stimulate the adrenal gland directly; it requires the intact pituitary. Administering exogenous corticotropin to hypophysectomized rats elevated plasma corticosterone levels and activation of the mitochondrial pathway. The pituitary-adrenal cortex-renal glutaminase I axis apparently operates as a functional unit in the homeostatic response to metabolic acidosis.