Ethanol Inhibitory Effect on Rat Kidney Brush Border Aminopeptidases

Abstract

Background/Aim: Confusing data have been reported about the effect of ethanol or its metabolic products on blood pressure. The pressor agent, angiotensin II (Ang II), is found to be susceptible to degradation by different enzymes known as angiotensinases. We have studied the effects of ethanol and L-NAME, an inhibitor of nitric oxide synthase, consumption on rat serum and kidney ectoenzymes: aminopeptidase N (APN) and aminopeptidase A (APA). Methods: Enzymatic activity of both enzymes was determined spectrophotometrically in serum and 10% homogenates of the rat kidney cortex using appropriate chromogenic substrates. Results: After 2 weeks of treatment with ethanol and L-NAME, blood urea and creatinine levels were significantly increased. The activities of APN (EC 3.4.11.2) and APA (EC 3.4.11.7) were reduced in serum as well as in kidney tissue during this period. L-NAME significantly attenuated activities of both enyzmes. Ethanol and L-NAME given simultaneously did not have an additional effect on the activity of investigated enzymes. Conclusion: Hypertension caused by chronic ethanol treatment as well as L-NAME administration could be associated with the reduction of APN and APA activity. Possible ethanol- and L-NAME-mediated inhibition of angiotensins degrading aminopeptidases could potentiate their effects on blood pressure.

Aminopeptidase N in arterial hypertension

“…In a rodent nitric oxide inhibition model of hypertension, i.e., rats treated with N(omega)-nitro-l-arginine methyl ester (L-NAME), less renal, aortic, and serum APN activity than in controls has been reported [84,85]. Although further studies are needed to determine the significance of APN in this model, a decrease in APN activity could be linked to the reported increase in the pressor response to Ang II by decreasing Ang III metabolism [86].…”

Contemporary aspects of the diagnostics of alcoholic liver disease

“…The effects of alcohol on the degree of liver injury depend on the dose, sex and age, as well on the concentration of alcohol and the length of its usage [3][4][5][6] . Alcohol through its toxic product, acetaldehyde, induces liver damage that can occur in the form of alcoholic fatty infiltration and alcoholic hepatitis, the changes which are reversible upon termination of alcohol intake, and alcoholic cirrhosis, which presents irreversible liver damage 2 .…”