Regulation of aldosterone secretion in dehydrated babies.

The factors controlling aldosterone secretion were measured in 12 patients with moderate to severe dehydration during the first year of life. Secondary hyperaldosteronism was present in all cases (mean plasma aldosterone concentration 414.6 ng/dl), as well as increased plasma cortisol levels (mean 49.7 microgram/dl). Plasma cortisol, an indirect parameter of stimulation of the adrenal cortex by ACTH, showed the highest correlation with plasma aldosterone (r = 0.82). Despite a mean elevation of 168 ng AT/ml/h the plasma renin concentration did not seem to play the dominant role in the regulation of aldosterone secretion in these infants. High serum sodium concentrations have a clearly inhibiting effect on aldosterone secretion as shown by the negative correlation coefficient of r = 0.80.