Caprylic acid infusion acts in the liver to decrease food intake in rats.
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.
Jambor de Sousa
Ulrike L
UL
Institute of Animal Sciences, ETH Zurich, 8603 Schwerzenbach, Switzerland.
Arnold
Myrtha
M
Langhans
Wolfgang
W
Geary
Nori
N
Leonhardt
Monika
M
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
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