AJP - Endocrinology and Metabolism, Vol 250, Issue 3 259-E264, Copyright © 1986 by American Physiological Society
Effect of hydrogen ion concentration on corticosteroid secretion
K. J. Radke, E. G. Schneider, R. E. Taylor Jr and R. E. Kramer
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.
