Plasma clearance of cortisol and 11-deoxycortisol in dogs

¹ Department of Surgery, The Johns Hopkins University School of Medicine, and Surgical Research Laboratories, Baltimore City Hospitals, Baltimore, Maryland

The chromogenic properties of cortisol and 11-deoxycortisol in the Porter-Silber reaction are identical. Recoveries of these substances from plasma by the Silber-Porter technique are similar, hence the plasma 17-hydroxycorticosteroid concentration reflects the concentrations of 11-deoxycortisol or cortisol in a quantitatively similar manner. The disappearance of 17-hydroxycorticosteroids was determined after intravenous infusions of cortisol and 11-deoxycortisol in adrenalectomized dogs. The exponential disappearance of 11-deoxycortisol (T1/2, 87 min) was more rapid than that of cortisol (T1/2, 104 min). Although this small difference in the slopes is only questionably significant, the 17-hydroxycorticosteroid concentration at each interval after cortisol infusion was two to three times greater than after 11-deoxycortisol. This concentration difference was statistically significant (P < 0.01) at all points. These data suggest that the distribution of injected 11-deoxycortisol is quite different from that of cortisol. As a result, the rate of adrenal corticogenesis is difficult to ascertain on the basis of plasma 17-hydroxycorticosteroid concentrations when, under the influence of Methopyrapone, the production of cortisol is replaced by that of 11-deoxycortisol.

Key Words: 11-deoxycortisol and blood • biologic half-life, cortisol and 11-deoxycortisol

Submitted on May 15, 1964