Stimulation of carnitine acylcarnitine translocase activity in heart mitochondria from hyperthyroid rats.
The effect of hyperthyroidism on fatty acid oxidation and on carnitine-acylcarnitine translocase activity in rat heart mitochondria has been studied. The rates of palmitoylcarnitine supported respiration as well as the carnitine-palmitoylcarnitine exchange reaction were both stimulated (approx. 36%) in heart mitochondria from hyperthyroid rats. Kinetic analysis of the carnitine-carnitine exchange reaction showed that thyroid hormone affects the Vmax of this process, while having no effect on the Km values. The level of cardiolipin was significantly higher (approx. 40%) in heart mitoplasts from hyperthyroid rats than from the control rats. It can be concluded that thyroid hormones produce a stimulation of heart mitochondrial carnitine translocase activity and that the basis of this effect is likely an increase in the cardiolipin content.
Paradies
G
G
Department of Biochemistry and Molecular Biology and CNR Unit for the Study of Mitochondria and Bioenergetics, University of Bari, Italy.
Ruggiero
F M
FM
Petrosillo
G
G
Quagliariello
E
E
D000818:Animals; D002308:Cardiolipins / Q000378:metabolism; D002331:Carnitine / Q000378:metabolism; D002333:Carnitine Acyltransferases / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D006980:Hyperthyroidism / Q000201:enzymology*; D008297:Male; D008929:Mitochondria, Heart / Q000201:enzymology*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010172:Palmitoylcarnitine / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D002308:Cardiolipins; D005227:Fatty Acids; D010172:Palmitoylcarnitine; D002333:Carnitine Acyltransferases; D002331:Carnitine