ISOLATION AND IDENTIFICATION OF ADRENOCORTICAL STEROIDS IN HUMAN PERIPHERAL PLASMA. I. A NATURALLY OCCURRING C21STEROID ACETATE (11-DEHYDROCORTICOSTERONE ACETATE) AND “FREE” TETRAHYDROCORTISONE IN NORMAL PLASMA*

Abstract

11-Dehydrocorticosterone acetate and tetrahydrocortisone were isolated from large quantities of normal peripheral human plasma and identified by chemical group reactivity, column and paper chromatography, and ultraviolet and infrared spectroscopy. A survey of the literature indicates that this is the first time that a naturally occurring C₂₁ steroid acetate has been isolated, and the possible significance of this finding with respect to the steroid transport mechanism is discussed. The presence of 11-dehydrocorticosterone acetate and tetrahydrocortisone in the “free” state indicates that the determination of Porter-Silber chromogens alone as an index of adrenocortical function must be accepted with caution. Estimation of the Porter-Silber chromogens includes the measurement of biologically inactive metabolites such as tetrahydrocortisone and tetrahydrocortisol while it does not measure biologically active 17-desoxycorticosteroids.