ADRENOCORTICAL ACTIVITY FOLLOWING CORTICOTROPHIN INJECTION AT LOW ADRENAL ASCORBIC ACID LEVEL

Abstract

It is known from the literature that 1 hour after an intravenous injection of corticotrophin into the hypophysectomized rat, the elevated plasma corticosteroid concentration has returned to the preinjection level. On the other hand, several investigators have reported that the adrenal ascorbic acid level is depressed for about a further 3 hours under similar experimental conditions. The effect of a second intravenous injection of corticotrophin during this period was studied. It was found, that a second significant rise of plasma corticosteroids occurred without any significant change in the adrenal ascorbic acid level. It is concluded, that the disappearance of ascorbic acid from the adrenal gland is not always directly quantitatively correlated with the amount of corticosteroids produced. These together with previous findings suggest that a more specific corticotrophin assay would result if the Sayers test (Sayers et al. 1948) were replaced by a measurement of plasma corticosteroids.