OBJECTIVE 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. CONCLUSIONS 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.