CELLULAR VARIATION IN THE UPTAKE AND METABOLISM OF CORTISOL BY CANINE ERYTHROCYTES

Abstract

ABSTRACT Samples of blood taken from 30 dogs were incubated with 1 μg cortisol/ml blood for 15 minutes. The RBC rapidly took up cortisol in varying amounts with the mean uptake being slightly greater than could be accounted for by equal distribution between plasma and RBC. The actual steroidal concentration associated with the RBC varied from 37.7 to 79.1 % in these 30 animals. It is suggested that some of the discrepancies in the literature relative to the quantitative association of cortisol with mammalian RBC may be related to the different kinds of RBC used to study uptake, as well as individual variation in cellular uptake. Also the finding of substantial quantities of cortisol associated with the RBC fractions of dog's blood suggests that no reliable estimates of blood steroidal concentration can be achieved without a knowledge of the quantity associated with the RBC. Cortisol reductase enzyme systems could not be detected in these cells. It is concluded that canine anucleated RBC do not possess the capacity to catabolize cortisol.