Hepatic histidase and muscle branched chain aminotransferase gene expression in experimental nephrosis

Protein and amino acid metabolism is altered during nephrotic syndrome. How ever, the expression of the amino acid degrading enzymes has not been well studied. The objective of this work was to assess the expression of hepatic histidase (Hal) and skeletal muscle mitochondrial branched chain amino tra nsferase (BCATm) in rats with experimental nephrotic syndrome induced by a single injection of puromycin aminonucleoside (150 mg/kg), Six days after t he injection rats were killed and hepatic Hal and skeletal muscle BCATm act ivities were measured. Also, total mRNA from both tissues was isolated and Hal and BCATm mRNA expression were analyzed by Northern blot. Rats with NS showed a reduction in food intake with respect to the control group. Hepati c Hal activity increased significantly in nephrotic and pair fed rats by 59 % compared to control group. This change in activity was associated with a corresponding increase in Hal mRNA abundance. On the other hand, skeletal m uscle BCATm activity and mRNA abundance were similar in the three groups st udied. These results suggest that the increase in Hal expression was associ ated with the reduced food intake and not to the NS. However, BCAT expressi on did not change indicating the importance of BCAA in body nitrogen conser vation. (C) 2000 Elsevier Science Inc. All rights reserved.