The aim of the work was study of influence of angiotensin-I-converting enzyme bloker on (the renal transport of endogenous nitrites and nitrates) in conditions of the single and long-term prescription of thyroxin to the rats. Rats were administered captopril (angiotensin-I-converting enzyme bloker) as water solution (20 mg/l) in composition of baking soda 24 hours before or during 24 hours from the moment of single introduction of T4 (50 mkg/100 g of body weight), or in combination with thyroxin within 7 days. Captopril was determined to decrease value of renal excretion of nitrates in all groups of animals that were administered thyroxin. Administration of captopril to the rats was shown to prevent retention of endogenous nitrites in blood plasma in animals that were given thyroxin within 7 days.
