Mineralocorticoids in the nephrotic syndrome of children.

Free aldosterone, the aldosterone precursor 18-OH-corticosterone, and 18-OH-deoxycorticosterone as well as the aldosterone metabolites 18-glucuronide and tetrahydroaldosterone were measured by radioimmunoassay in the urine of 24 children with the nephrotic syndrome. In addition renin activity, aldosterone and corticosterone were measured in plasma. All children with manifest edema showed increased values of one or more of the measured aldosterone parameters indicating hyperaldosteronism. In non-edematous patients one or more parameters were increased in 9 of 16 patients. Free aldosterone, tetrahydroaldosterone and 18-OH-corticosterone proved to be the most sensitive urinary parameters for the detection of increased mineralocorticoid function. Free urinary aldosterone was correlated with sodium excretion and with serum albumin. The pathogenesis of hyperaldosteronism in the nephrotic syndrome and its role in the development of edema are discussed.