Influence of Hormone Status on Enzymes Released from Renal Cortical Slices of Wistar Rats

Release of some cytosolic (aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase) and brush border (γ‐glutamyltransferase and alkaline phosphatase) enzymes from renal cortical slices was studied in vitro. Renal cortical slices were prepared freehand from 3‐month‐old male and female Wistar rats of different hormonal status. Some male and female rats were castrated at 1 month of age and a portion of castrated males and of naive males and females were s.c. treated with testosterone (10 mg kg−1 body wt.) on alternate days for 3 weeks. Females had higher alanine aminotransferase (77.5 ± 2.8 nmol 100 mg−1 tissue), lactate dehydrogenase (5.01 ± 0.24 μmol) and alkaline phosphatase (1.63 ± 0.15 mol) activities than male rats (20.4 ± 0.9, 3.99 ± 0.19 and 0.91 ± 0.02, respectively). On the contrary, aspartate aminotransferase and γ‐glutamyltransferase were similar. Among cytosolic enzymes, alanine aminotransferase and lactate dehydrogenase appeared to be sexual hormone‐dependent enzymes: castration significantly increased enzyme activities in males (49.6 ± 1.1 for the former; 5.30 ± 0.15 for the latter) and caused significant decreases in females (alanine aminotransferase only 47.1 ± 1.5), whereas testosterone pretreatment decreased activities in cortical slices from female (48.1 ± 3.6 and 3.81 ± 0.07, respectively) and castrated male (27.4 ± 1.8 and 4.05 ± 0.15, respectively). Moreover, exogenous testosterone increased aspartate aminotransferase in males (1.05 ± 0.01 μmol) and castration increased it in both sexes. The activity of brush border enzymes was increased by testosterone pretreatment and decreased by castration (mainly alkaline phosphatase).