title: Caprylic acid infusion acts in the liver to decrease food intake in rats.
abstract: Hepatic portal vein (HPV) infusion of the medium chain fatty acid caprylic acid (CA; 2.3 mg/min, 40 microl/min) for 90 min beginning at dark onset in 18-h food-deprived male rats reduced the size of the first nocturnal meal about 40% (P < 0.01) and reduced 24-h food intake by about 15% (P < 0.001). Identical infusions into the vena cava affected neither initial meal size nor food intake. HPV CA infusion attenuated the postprandial decreases in plasma free fatty acids (P < 0.01) and beta-hydroxybutyrate (P < 0.01). HPV CA infusions did not significantly reduce nocturnal saccharine intake in a two-bottle conditioned taste aversion test, and there was no association between the saccharine intake on the test day and the feeding-inhibitory effect of CA on the conditioning day. HPV CA infusion did not affect plasma concentrations of corticosterone or of the pro-inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha. HPV CA infusion did not increase plasma concentration of the liver enzyme alanine aminotransferase, but did increase plasma concentration of gamma-glutamyl transferase, although not into the pathophysiological range. These data indicate that CA acts in the liver to produce a signal that inhibits feeding and that this inhibitory effect may be related to increases in hepatic fatty acid oxidation rather than be the result of aversion or toxicity.
authors.affiliation: Institute of Animal Sciences, ETH Zurich, 8603 Schwerzenbach, Switzerland.
authors.forename: Ulrike L
authors.initials: UL
authors.lastname: Jambor de Sousa
authors.forename: Myrtha
authors.initials: M
authors.lastname: Arnold
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Langhans
authors.forename: Nori
authors.initials: N
authors.lastname: Geary
authors.forename: Monika
authors.initials: M
authors.lastname: Leonhardt
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D001067:Appetite Depressants; D002210:Caprylates / Q000008:administration & dosage / Q000494:pharmacology*; D002406:Catheterization, Peripheral; D003345:Corticosterone / Q000097:blood; D003627:Data Interpretation, Statistical; D004435:Eating / Q000187:drug effects*; D005227:Fatty Acids / Q000378:metabolism; D005746:Gastric Emptying / Q000187:drug effects; D007249:Inflammation / Q000097:blood / Q000378:metabolism; D007262:Infusions, Intravenous; D015850:Interleukin-6 / Q000097:blood; D007601:Jugular Veins; D007659:Ketones / Q000378:metabolism; D008099:Liver / Q000187:drug effects*; D008297:Male; D010084:Oxidation-Reduction; D011169:Portal Vein; D051381:Rats; D017207:Rats, Sprague-Dawley; D013315:Stress, Psychological / Q000378:metabolism; D013649:Taste / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014684:Venae Cavae
chemical_list: D001067:Appetite Depressants; D002210:Caprylates; D005227:Fatty Acids; D015850:Interleukin-6; D007659:Ketones; D014409:Tumor Necrosis Factor-alpha; C031492:octanoic acid; D020155:3-Hydroxybutyric Acid; D003345:Corticosterone