title: Effect of hydrogen ion concentration on corticosteroid secretion.
abstract: The direct effects of changes in extracellular hydrogen ion (H+) concentration on corticosteroid secretion under basal and ACTH-stimulated conditions were studied in isolated, perfused canine adrenal glands. Changes in extracellular H+ concentration were produced by altering either PCO2 or [HCO-3] of the Krebs-bicarbonate perfusate. Alkalosis markedly inhibited ACTH-stimulated aldosterone secretion. Moreover, within the range of pH from 7.19 to 7.85, there was a positive correlation between H+ concentration and the fractional secretion of aldosterone but a negative correlation between H+ concentration and the fractional secretion of corticosterone and 18-hydroxycorticosterone in response to ACTH. In contrast, neither acidosis nor alkalosis had a significant, direct effect on basal or ACTH-stimulated cortisol secretion. We conclude that 1) H+ concentration modulates the stimulatory effect of ACTH on aldosterone secretion by a direct action on the adrenal cortex, 2) acid-base disturbances are specific to the zona glomerulosa of the canine adrenal gland, and 3) H+ concentration may influence events occurring late in the pathway for aldosterone biosynthesis.
mesh_terms: D015069:18-Hydroxycorticosterone / Q000378:metabolism; D000136:Acid-Base Equilibrium; D000305:Adrenal Cortex Hormones / Q000378:metabolism*; D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000378:metabolism; D000818:Animals; D003345:Corticosterone / Q000378:metabolism; D004285:Dogs; D005260:Female; D006854:Hydrocortisone / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008297:Male; D010477:Perfusion; D013268:Stimulation, Chemical
chemical_list: D000305:Adrenal Cortex Hormones; D000450:Aldosterone; D015069:18-Hydroxycorticosterone; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone; D006854:Hydrocortisone