Compared expression levels of ornithine transcarbamylase and carbamylphosphate synthetase in liver and small intestine of normal and mutant mice.

Enzymatic assay, electrophoretic immunoblotting and RNA dot-blot techniques were employed to investigate the expression of the ornithine transcarbamylase (OTC) gene in liver and small intestine of Sparse fur mice with abnormal skin and hair (Spf-ash) and Sparse fur mice (Spf) which exhibit an X-linked OTC deficiency. We found a reduced OTC activity in these two tissues. We now show that this reduction is less pronounced in the intestine than in the liver of the Spf-ash strain. During the first 2 weeks of life, the deficiency appears to be less severe than in the adult mice. The enzymatic activity of carbamylphosphate synthetase I (CPS), another enzyme of the urea cycle, is significantly modified in the Spf mutant strain only.