Neonatal Weight Loss and Aldosterone Excretion

Abstract

To the Editor:— Aldosterone excretion in urine has been measured in few infants and newborns. The aim of this study was to determine serially normal aldosterone excretion during the newborn period and to see whether there was a relationship between the initial neonatal weight loss and aldosterone excretion. Four normal premature male infants were studied because of the relative ease of collecting 24-hour urine samples in males. Their birth weights ranged between 1,814 to 2,267 gm (4 to 5 lb) and their gestational ages were between 33 and 35 weeks. Three 24-hour urine samples were collected from each: (1) during the first 24 hours; (2) during the 24 hours when they had reached the lowest weight; and (3) during the 24 hours when the regained their birth weight. These infants were fed 5% dextrose in water at 4, 8, and 12 hours of age, and then were fed a milk