The aim of the study was to investigate how inhibition of the converting enzyme activity would affect the concentration of potassium and magnesium in the plasma and erythrocytes of calves in their early neonatal age. The studies were carried out on 10 Black-and-White calves over the first seven days of their life. In order to block the angiotensin I converting enzyme, the calves was administered per os 0.2 mg·kg^-1 b.w. of captopril (Captopril – Jelfa). The results suggests that captopril administration results in increasing potassium and magnesium concentrations in calf blood plasma and in reduction of these electrolytes levels in erythrocytes. The ratio of potassium concentration inside erythrocytes to blood plasma potassium concentration after captopril administration changed only slightly, like the ratio of magnesium concentration inside erythrocytes to that in blood plasma.

125-133