Quantitative and Temporal Studies on Effect of Dexamethasone on Corticosterone Secretion in the Rat.

Abstract

The rat corticosterone secretion rate determined fluorimetrically from 3-minute samples of adrenal effluent (123 ± 5.3 μg/kg/adrenal/hr) agrees well with values reported for more extended collection periods and analyzed by other methods. Dexamethasone-21-phosphate, a non-fluorescing, corticotropin-suppressing, synthetic steroid was found to produce maximal suppression of the corticosterone secretion rate 4 to 8 hours following a single dose. The technic described may be applied to assays of corticotropin itself or assays of corticotropin suppressing activity of other non-fluorescing agents.