[Activity of 5-alpha- and 5-beta-steroid reductases in subcellular liver structures from rats bearing Walker carcinosarcoma].

Change in the activity of cytoplasmic 5 beta- and microsomal 5 alpha-steroid reductases was studied in tumor bearing rats. As shown by thin-layer chromatography conversion of 3H-corticosterone into 5-alpha and 5 beta-dihydro-compounds was decreased 3-fold in rats bearing Walker tumor. Activity of both these enzymes exceeded the initial level 2-3-fold in presence of exogenous NADPH. At the same time, activation of glucose 6-phosphate dehydrogenase was accompanied by simultaneous alteration in content of transcortin-bound corticosterone in rat blood plasma. 5 alpha-reductase was detected in membranes of liver tissue endoplasmic reticulum and in the fraction of free polyribosomes.