Association of Tritium-Labelled Estradiol, Progesterone and 17α-Hydroxyprogesterone with the Proteins of the Serum and Cerebrospinal Fluid in the Rhesus Monkey

Abstract

The electrophoretic profiles of the proteins in the serum and cerebrospinal fluid (CSF) of the rhesus monkey were studied by polyacrylamide gel electrophoresis. The association of tritium labeled estradiol (3H-E), progesterone (3H-P) and 17.alpha.-hydroxyprogesterone (3H-17OHP) with these proteins was studied under in vitro and in vivo conditions. The CSF was contained besides albumin, at least 4 globulins with similar electrophoretic mobilities as those in the serum. The electrophoretic mobilities of these globulins were Ralb 0.4, 0.6, 0.8 and 0.9. The electrophoretic profiles of the monkey serum and CSF proteins were similar to those described for human serum and CSF. 3H-E and 3H-P were associated with serum globulins of Ralb 0.4 and 0.8, respectively, in the in vitro and in vivo studies. The respective Ralb of these 2 globulins were similar to the testosterone-estradiol binding globulin and cortisol binding globulin in human serum. 3H-170HP was associated with several globulins under both in vitro and in vivo conditions. In marked contrast to the in vitro studies, radioactive products were associated with albumin in vivo. These products may be steroidal conjugates derived from the systemic metabolism of the administered steroids. No radioactivity was associated with the CSF protein after in vitro incubation with any of the 3 3H-steroids. In the in vivo studies radioactivity was associated with the CSF proteins similar to those in the serum and associated with the administered steroids.