Alterations in enzymes involved in fat metabolism after acute and chronic altitude exposure

involved in fat metabolism after acute and chronic altitude exposure. J Appl Physiol 90: 17–22, 2001.—The purpose of this study was to examine the effect of acute (24 h) and chronic (5 wk) hypobaric hypoxic exposure equivalent to a simulated altitude of 4,300 m (446 mmHg) on the enzymes of fat metabolism. Heart, liver, and skeletal muscle were taken from 32 male Sprague-Dawley rats. Altitude exposure did not affect the activity of citrate synthase in any of the tissues, suggesting that mitochondrial content was unchanged. Car-nitine palmitoyltransferase-I (CPT-I) activity was signifi-cantly reduced in the heart by both acute and chronic high altitude exposure compared with controls. A similar reduc-tion was found for CPT-I activity in extensor digitorum longus after acute and chronic exposure compared with con-trol animals. CPT-I activity was not affected by altitud