Correlation of Calcium and Acid-Base Metabolism

Abstract

The suggestion that the higher afternoon values of somatomedin activity resuIt from a decrease in inhibition of the somatomedin bioassay by cortisol (Van den Brande, Van Buul, Heinrich, Van Roon, Zurcher and Van Steirtegem 1975) are not supported by the findings of this study where cortisol and somatomedin both increase from 0900 hand both have high values between 1200 and 1400 h. Furthermore, as there is a single peak 01' somatomedin activity but two peaks in cortisol secretion, it would appear that increased plasma cortisol does not produce a decrease in somatomedin production. It would thus appear that the observed cireadian variation of somatomedin activity is independent of cortisol secretion.