ACID-HYDROLYZABLE CORTICOIDS OF SERUM*

Abstract

SINCE the work of Nelson (1) there have been many studies concerning blood corticoids. These have raised questions concerning the exact significance of measurements of chloroform extractable blood corticoids, hereinafter called free corticoids. Were there conjugated as well as free blood corticoids?What was the significance of conjugated blood corticoids, if such existed? Were the free blood corticoids an insignificant part of the total blood corticoids and, if so, were their measurements of any value? Finally, the question arose, if there were conjugated blood corticoids, were they important as active hormones or could they be converted to active forms of hormone if they were inactive? The present study attempts to answer some of these questions. METHODS AND SUBJECTS The method used for the measurement of conjugated corticoids was essentially an adaptation of the method of Nelson and Samuels (1) for free 17,21-dihydroxy-20-ketosteroids in blood. Either plasma or serum was extracted according to their method and the free corticoids measured. The serum or plasma following the third extraction was then hydrolyzed with acid, and the material once more extracted according to the original method of Nelson and Samuels; and the acid hydrolyzable corticoids were then measured. Nearly all the measurements reported here were made on serum. The details for the method are as follows: