Role of Ca2+ in response of adrenal glomerulosa cells to angiotensin II, ACTH, K+, and ouabain

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Abstract
The effects of Na+-K+-ATPase inhibition by ouabain and blockage of Ca2+ influx into the cell by verapamil and lanthanum on the response of isolated rat adrenal glomerulosa cells to angiotensin II, ACTH, and K+ were studied. Ouabain significantly increased basal aldosterone output at a concentration of 10(-5) mol/liter, whereas at 10(-3) mol/liter basal secretion was unaffected. Steroidogenic response to angiotensin II was significantly potentiated at concentrations of ouabain of 10(-5) mol/liter, but responses to angiotensin II, ACTH, and K+ were inhibited by 10(-4) and 10(-3) mol/liter of ouabain. The Ca2+ antagonist verapamil (10(-6) to 10(-4) mol/liter) decreased basal aldosterone secretion as well as the response to angiotensin II, ACTH, and K+. The effects of ouabain (10(-5) mol/liter) on basal and stimulated steroidogenesis were abolished by verapamil (10(-4) mol/liter). Lanthanum decreased basal and angiotensin II, ACTH, and K+ induced aldosterone secretion. The effects of ouabain (10(-5) mol/liter) on basal and stimulated aldosterone biosynthesis were blocked by lanthanum. These results suggest that Ca2+ mediates the effects of angiotensin II, ACTH, K+ and Na+-K+-ATPase inhibition on aldosterone biosynthesis. Ca2+ may be the final common intracellular messenger of most aldosterone secretagogues.