Increased expression of carnitine palmitoyltransferase I gene is repressed by administering L-carnitine in the hearts of carnitine-deficient juvenile visceral steatosis mice.

The juvenile visceral steatosis (JVS) mouse is a novel mutant animal for studying systemic carnitine deficiency. The importance of the model has been pointed out in carnitine-deficient cardiac hypertrophy, since cardiomyopathy has been often improved after oral carnitine therapy in human systemic carnitine deficiency. To understand the effects of carnitine deficiency on gene expression in the heart, we tried to find the genes regulated by carnitine by means of a modified differential display procedure. Carnitine palmitoyltransferase I (CPT I) was one of the isolated genes. The level of CPT I gene expression in the ventricles of the JVS mice was at least three- to sixfold that of normal mice as judged by reverse transcription-polymerase chain reaction (RT-PCR). When the JVS mice were treated with carnitine, CPT I gene expression was repressed to the level of normal mice. Therefore, the increased expression of the CPT I gene was associated with carnitine deficiency.