Hyperpolarization of the cell membrane of mouse hepatocytes by fatty acid oxidation.
The effect of palmitate and metabolizable and nonmetabolizable monosacharides (D-glucose, D-fructose and 2-deoxy-D-glucose = 2-DG) on the membrane potential (Vm) of mouse hepatocytes was investigated employing a superfused mouse liver slice technique. Palmitate hyperpolarized the liver cell membrane in a concentration dependent manner whereas the monosaccharides tested did not. When mice were fed a fat-rich diet, the hyperpolarisation was greater in comparison to mice fed a low fat diet. The hyperpolarization was reversed by ouabain, an inhibitor of the Na+/K(+)-ATPase, by the K(+)-channel blockers tetra-ethyl-ammonium (TEA) and cetiedil and by three inhibitors of fatty acid oxidation (2-bromopalmitate, 2-bromooctanoate and 4-pentenoate). The results suggest that hyperpolarization of the liver cell membrane is due to fatty acid oxidation and that both activation of Na+/K(+)-ATPase and opening of K(+)-channels are involved. The implications of these findings with regard to control of food intake by fatty acid oxidation are discussed. The results are consistent with a role of the hepatic membrane potential in control of food intake by fatty acid oxidation.
Rossi
R
R
Institut für Veterinär-Physiologie, Universität Zürich, Switzerland.
Geronimi
M
M
Gloor
P
P
Seebacher
M C
MC
Scharrer
E
E
D000818:Animals; D002210:Caprylates / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology; D004041:Dietary Fats / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D005260:Female; D005632:Fructose / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects*; D051379:Mice; D010042:Ouabain / Q000494:pharmacology; D010084:Oxidation-Reduction; D010168:Palmitates / Q000494:pharmacology
D002210:Caprylates; D004041:Dietary Fats; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D010168:Palmitates; C022776:2-bromopalmitate; C019279:2-bromooctanoic acid; D005632:Fructose; D010042:Ouabain; D003847:Deoxyglucose; C009785:4-pentenoic acid; D005947:Glucose