Hepatic mitochondrial proteins in congenitally hyperammonemic spf mice: effect of acetyl-L-carnitine

The sparse-fur (spf) mutant mouse has an X-linked deficiency of hepatic ornithine transcarbamylase (OTC), and develops hyperammonemia immediately after weaning and maintains it throughout its life span. We have studied the effects of acetyl-L-carnitine (ALCAR) on the hepatic mitochondrial proteins of the chronically hyperammonemic spf mice. Two different age groups of mice were studied, the weanlings (3 weeks) and the adult mice (8 weeks). Our results indicate that in the mitochondrial matrix, the untreated chronic hyperammonemia induced a significant increase in the quantity of 54.4-kDa protein in spf adult mice. After ALCAR treatment, in spf adult mice, the quantities of the 54.4-kDa, 63.8-kDa, and 129-kDa matrix proteins were significantly increased. In the mitochondrial inner membrane fraction of the spf weanling mice, a 53.5-kDa protein was significantly increased by ALCAR treatment. Our results show that: (a) chronic hyperammonemia has altered the mitochondrial matrix protein profile in spf mice, that (b) ALCAR has a modulating effect on various matrix and inner membrane proteins, and that (c) there was no effect of hyperammonemia or ALCAR treatment on the outer membrane proteins.