Metabolism and interconversion of dehydroisoandrosterone and dehydroisoandrosterone sulfate.

Abstract

In order to study the dynamic aspects of removal, conjugation and transformations of free dehydroisoandrosterone (DHA) and the transformations, particularly hydrolysis, of dehydroisoandrosterone sulfate (DHAS), DHA-7α-3H was administered to two subjects and DHAS-7α-3H was given to a single patient. Within 2 hr after the injection of DHAS-3H, free DHA contained 0.19% of the radioactivity in plasma and maintained this value during the remaining 5 hr of the study. Androsterone (A) and etiocholanolone (E) isolated from the sulfate and glucosiduronate fractions of plasma were also radioactive demonstrating that a portion of them was derived from the tracer, presumably via hydrolysis of DHAS. Within 30 min after injection of DHA-3H, 90% of the radioactivity in the plasma was present in steroid conjugates of which 30% consisted of glucosiduronates. By 7 hr, over 99% of the 3H was present in the conjugates, glucosiduronates comprising less than 10% of the fraction. At this time, circulating free DHA contained 0.7% of the plasma radioactivity. These observations of a rapid and continuing hydrolysis of DHAS as well as the persistence of free DHA in the circulation provide evidence for the presence of a baseline “level” of free DHA below which fluctuating plasma concentrations of the hormone (from episodic secretion) do not fall.