Suppression of T-3- and fatty acid-induced membrane permeability transition by L-carnitine

Cytochrome c (Cyt. c) is known to be released from the mitochondria into th e cytosol by means of the membrane permeability transition (MPT) mechanism, thereby activating caspase cascade activity, and inducing cell apoptosis. Recently we reported that L-carnitine suppressed palmitoyl-CoA-induced MPT as well as apoptosis in some cell types (Biochem. Pharmacol, in press). In the present study T-3 was found to induce MPT and Cyt. c release, while cyc losporin A (CsA), bovine serum albumin (BSA) and L-carnitine were found to inhibit this action in a concentration-dependent manner. Similarly, long ch ain fatty acid (LCFA) also induced MPT and Cyt. c release, which was then i nhibited by CsA, BSA and L-carnitine. From these results the authors postul ate that T-3-induced MPT is in part regulated by fatty acid metabolism thro ugh a dynamic balance between LCFAs and L-carnitine. (C) 2001 Elsevier Scie nce Inc. All rights reserved.