Secretion rate and metabolism of the sulfates of cortisol and corticosterone in newborn infants.

Abstract

3H-cortisol and 14C-cortisol sulfate, and 3H-corticosterone and 14C-corticosterone sulfate, were injected intravenously to human newborns aged 2 days. From 49 to 79% of 3H and from 62 to 100% of 14C were accounted for in their urine. Of the total amount of tritium present in the urine only small proportions were extractable. The amounts extracted in both the sulfate (3–18%) and glucuronide (1.3–13%) fractions were substantially greater than in the unconjugated fraction. Almost negligible amounts of 14C appeared in either the unconjugated or glucuronide fractions. The sulfate fraction consisted of 2 main components: the sulfates of cortisol and corticosterone, which were devoid of tritium; and a highly polar fraction which contained both 14C and most of the tritium extractable in this fraction. From the specific activities of tetrahydrocortisone and tetrahydro-11-dehydrocorticosterone purified from the glucuronide fraction, and from those of the sulfates of cortisol and corticosterone, the secretion rate of cortisol was calculated as ranging from 12.6 to 16.4 mg/m2/day; that of corticosterone from 4.6 to 18.3; those of their respective ester sulfates: 0.12–0.35 and 1.8–5.4. The findings indicate that cortisol and corticosterone are not sulfurylated prior to being metabolized; that a relatively substantial amount of their metabolites may be excreted as sulfate esters; and that corticosterone and its sulfate may represent very significant secretory products of the adrenal in the human newborn.