Effect of chorionic gonadotropin on lactate dehydrogenase and alcohol dehydrogenase activity in the pathologically altered liver

Abstract

Chorionic gonadotropin is shown to alter lactate dehydrogenase and alcohol dehydrogenase activity in the pathologically altered liver and to exert a regulatory effect on the catalytic properties of these enzymes. Key Words: chorionic gonadotropin; lactate dehydrogenase; alcohol dehydrogenase; liverOne approach to the management of chronic hepatitis and of cirrhosis consists in the use of agents that stimulate regeneration of the liver. It has been shown that chorionic gonadotropin (CG) stimulates liver regeneration and the reversal of pathological changes, with the result that the structure and function of this organ return toward normal [6]. CG promotes enhanced RNA synthesis and lowers the activity of lysosomal enzymes by elevating the activity of organ-specific enzymes (urokinase, fructose-l-phosphatase) [1,5]. Preliminary studies have indicated that CG has a direct effect on the catalytic properties of lactate dehydrogenase (LDH) in vitro [3], which suggests that this hormone may act as a nonspecific regulator of enzyme activity in the cell.The purpose of the present study was to examine how CG might affect the regulation of LDH and alcohol dehydrogenase (ADH) activity in the pathologically altered liver. MATERIALS AND METHODSThe effect of CG on LDH and ADH activity in the pathologically altered liver was studied on a model of toxic hepatitis produced in randomly bred male rats by administering them subcutaneously a 66% solution of carbon tetrachloride (CC14) in a dose of 0.3 ml 4 times per week over a 3-month period. After the discontinuation of CC14 injections, some of the rats were treated with CG and some were left untreated. CG was injected subcutaneously in a dose of 75 units per 100 g body weight. The animals were killed by decapitation 2 and 30 days after the start of hormone therapy. The control group consisted of intact rats. Activities of the direct and reverse LDH and ADH reactions were measured in liver homogenates and expressed in nrnol NADH/min per mg protein [4]. Table 1, the activity of the oxidative enzymes LDH and ADH was altered in the homogenates of livers from rats with toxic hepatitis. Thus, the activity of the direct LDH reaction was higher by 69% and that of the reverse LDH reaction lower by 40% than in the control group of intact rats. The activity of the direct and reverse ADH reactions was lower in both cases, by 51% and 55%, respectively. The reduced capacity of the liver to effect biotransformation of alcohols and aldehydes and the predominantly aerobic type RESULTS As shown in