METABOLISM OF STEROIDS: THE REMOVAL OF EXOGENOUS 17-HYDROXYCORTICOSTERONE FROM THE PERIPHERAL CIRCULATION IN DOGS1

Publisher Website
Google Scholar
Abstract
A study was undertaken to determine whether the disappearance rate of exogenous cortisol could be used to evaluate the influence of experimental conditions or agents upon cortisol metabolism. It was found that the half-life of exogenous cortisol in a given dog was not very consistent from one day to another. Therefore, in a single experiment, the half-life of exogenous cortisol was obtained and then the influence of an administered agent upon this half-life was determined. The disappearance rate of exogenous cortisol was not influenced by subsequent administration of saline or dextrose. Neither a second injection of cortisol, nor small doses of ACTH (0.5–2.0 i.u.), altered the disappearance rate of cortisol, even though there was an increase in plasma concentration of the steroid. Larger doses of ACTH apparently caused a decrease in the rate of cortisol disappearance. Although this technic produces a “physiological hypophysectomy” it is not satisfactory for assay of ACTH. However, it does permit evaluation of the influence of conditions or agents on the disappearance rate of circulating cortisol.