Liver denervation affects hepatocyte mitochondrial fatty acid transport capacity.
The effect of liver denervation on the activity of hepatic carnitine palmitoyltransferase (CPT) system, which catalyses the transfer of long-chain fatty acids into the mitochondria, was studied in rats. Noradrenaline content in phenol-denervated liver (D) was reduced by 87%. CPT I and II activities (measured by radioassay after detergent separation of the enzymes) were decreased (p < 0.001) in D (2.6 +/- 0.1 and 0.68 +/- 0.2 nmol min(-1) mg(-1) protein, respectively) as compared with controls (4.7 +/- 0.3 and 2.5 +/- 0.2 nmol min(-1) mg(-1) protein, for CPT I and II, respectively). A less intense immunoreactive band for denervated liver CPT II was obtained after Western blotting. Concomitantly, long-chain fatty acid incorporation (p < 0.001), evaluated after administration of [14C]-oleate and total fat content (p < 0.001) were increased in D in relation to controls, while incorporation of exogenous [14C]-oleate into secreted VLDL, was decreased (p < 0.01). The effect of sympathetic denervation on CPT activity was different from that evoked by adrenodemedullation, which caused an augmentation of CPT activity (p < 0.01), when compared with the liver of intact rats. The effects of denervation and adrenodemedullation on the other parameters of lipid metabolism studied, were similar. The results strongly suggest a role of liver sympathetic innervation in the regulation of liver lipid metabolism.
Carreño
Flávia R
FR
Laboratory of Histophysiology, Department of Histology and Embryology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Seelaender
Marília C L
MC
D000313:Adrenal Medulla / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D015153:Blotting, Western; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D003714:Denervation; D005227:Fatty Acids / Q000378:metabolism*; D022781:Hepatocytes / Q000378:metabolism*; D050356:Lipid Metabolism; D008099:Liver / Q000294:innervation*; D008930:Mitochondria, Liver / Q000378:metabolism*; D019301:Oleic Acid / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014304:Triolein / Q000378:metabolism
D005227:Fatty Acids; D014304:Triolein; D019301:Oleic Acid; D002334:Carnitine O-Palmitoyltransferase