VARIATIONS BY EPINEPHRINE OF HEPATIC AND SERUM AMINOTRANSFERASES AND LACTATE DEHYDROGENASE IN THE RAT

Incubation of rat hepatocytes with epinephrine inhibited alanine aminotransferase (ALT) (80%) and aspartate aminotransferase (AST) (53%) activities with no effect on lactate dehydrogenase (LDH) activity. Injection of epinephrine caused a progressive increase with time in hepatic LDH activity, being 52% at 24 h. Preinjection with propranolol eliminated the hormone effect and caused further inhibition (28%) of the enzyme activity. Liver ALT activity in ephinephrine-treated animals decreased by 37% at 24 h, "_.er which it rose again to the control levels at 48 h. Propranolol raised epinephrine-induced enzyme inhibition up to 53%. Phentolamine, however, abolished the inhibitory effect. The activity of hepatic AST was not affected by epinephrine. Plasma ALT and LDH activity increased in epinephrine injected rats by 55% and 75%, respectively, but AST activity did not change. Propranolol alone stimulated serum ALT (41 %) and AST (21 %) activities. The data suggest that epinephrine exerts its effects on these enzymes through a-receptor activation and/or via the cell lesion resulting in the change of intra- and extracellular enzyme levels.