Abstract
In this review, we summarize our recent reports: the roles of carnitine in the general metabolism and the central nervous system, and the effects of carnitine administration to the fasted carnitine-deficient juvenile visceral steatosis (JVS) mice. Fasting reduced locomotor activity (LA) of JVS mice. Single carnitine administration caused an increase of the reduced LA and the fat expenditure, and the effects were prolonged for at least two days after the administration, although the carnitine concentration in blood and tissues returned to the original carnitine-deficient level. In JVS mice, fasting also caused a decreased percentage of c-Fos positive orexin neurons in the lateral hypothalamus (ameliorated by carnitine administration) and a reduced orexin-A concentration in the cerebrospinal fluid. These results suggest that the low tissue carnitine level of JVS mice is not the sole rate-limiting factor of general fatty acid oxidation, and the reduced LA in fasted JVS mice is related to the inhibition of orexin neuronal activity.
