The effects of exogenic and metabolite-induced insulin and glucagon on rat hepatocyte serine proteinase metabolism were studied. The enzyme functioning time was assessed, as were the constants of synthesis and disintegration rates of proteinase localized in various parts of the cell. Chromatographic, electrophoretic, and radioimmunochemical methods of analysis were used in the study. The presented numerical values are the results of a series of ten experiments, processed by variation statistics method. Exposure to exogenic insulin resulted in a reduction of synthesis rate and of newly synthetized proteinase concentration in the cytosol fraction, this being parallelled by a negligible prolongation of functioning enzyme life time and an increase in the rate of enzyme supply to peroxisomes. Exogenic glucagon stimulated by 7.3 times the rate of cytosol proteinase synthesis. Glucagon administration resulted in an increase of the rate of supply of newly synthetized molecules of the enzyme to mitochondria and peroxisomes. The data presented evidence that hormonal effects on protein metabolism processes in organs and tissues may be mediated by nonlysosomal proteolysis regulation.