Effect of sodium valproate on renal cell brush-border enzymes in rats

The effect of sodium valproate (200 mg/kg body weight) on renal cells was investigated during a 10-day trial, by determining the catalytic activities of alanine aminopeptidase, gamma-glutamyltransferase and alkaline phosphatase in the membrane cell brush-border of the renal proximal tubules. Four days after the administration of sodium valproate, a significant increase was observed in the volume of urine (9.2 +/- 4.2 ml/18-h volume; control group, 3.06 +/- 1.8 ml/18-h volume), and in the catalytic activities of gamma-glutamyltransferase (2.69 times that measured in the control group) and alkaline phosphatase (3.02 times that measured in the control group) in urine. After prolonged treatment the urine became alkaline (pH = 10.5 on day 10), thereby excluding alanine aminopeptidase as a useful indicator of renal cell changes following the administration of sodium valproate. The activities of alkaline phosphatase and gamma-glutamyltransferase in isolated vesicles of renal brush-border membrane cells were significantly increased (p < 0.05) and decreased, respectively. On the basis of the results obtained, we believe that the determination of the catalytic activities of gamma-glutamyltransferase and alkaline phosphatase in urine might prove useful for the follow-up of the renal cell state during therapy with sodium valproate.