Response of plasma ACTH and adrenocortical hormones to potassium loading in essential hypertension

The effect of potassium loading on plasma adrenocortical hormones concentrations in 9 patients with essential hypertension (EH) was investigated. The plasma renin activity (PRA), plasma concentrations of growth hormone (GH), ACTH, cortisol, deoxycorticosterone (DOC), 18-hydroxy-deoxycorticosterone (18-OH-DOC) and aldosterone, and serum electrolytes were measured before and after potassium chloride (KC1) infusion (0.33 mEq/kg/h, for one hour). The KC1 infusion caused significant increases in serum potassium levels and plasma levels of GH, ACTH, cortisol, DOC, 18-OH-DOC and aldosterone, while PRA remained unchanged. Regression analysis at 30 min revealed significant positive correlations between delta ACTH and delta cortisol, between delta ACTH and delta DOC, between delta ACTH and delta 18-OH-DOC. However, the relationship between delta ACTH and delta aldosterone was not statistically significant. These results suggest that (1) acute potassium loading causes a significant increase in the plasma ACTH level and increased levels of adrenocortical hormones may be produced by increased ACTH secretion, and (2) it may be considered that a part of the increased level of plasma aldosterone following acute potassium loading may arise from increased ACTH secretion in EH.