Dehydroisoandrosterone is secreted episodically and synchronously with cortisol by normal man

In 4 studies in a normal man it was demonstrated that dehydroisoandrosterone (DHA) was secreted episodically and synchronously with cortisol. The studies were done at 20-min intervals in the early morning (0340–0720 hr) and in the late afternoon (1540–1920 hr). A double isotope derivative method was developed for measurement of the low concentrations of DHA in plasma. DHA never reached zero concentration in plasma, whereas cortisol did. This is explained by the contribution to DHA by hydrolysis of the relatively abundant circulating DHA sulfate. Because of the low plasma concentration a high degree of biological activity can be implied for DHA, the function of which is at present unknown.