Acute high-fat diet paradigms link galanin to triglycerides and their transport and metabolism in muscle.
To compare the effects of acute exposure to dietary fat to those of chronic exposure, Sprague-Dawley rats were given a high-fat diet (50% fat) or moderate-fat diet (25% fat) for 1 day, 2 h or 3 weeks. With measurements of various parameters, the high-fat diet for 21 days produced the expected changes of: (1) a significant increase in total caloric intake and dissected fat pad weights; (2) a rise in leptin and the metabolites, triglycerides (TG), non-esterified fatty acids and glucose; (3) an increase in muscle beta-hydroxyacyl-CoA dehydrogenase (HADH) and adipose lipoprotein lipase (aLPL) activity, along with a decrease in LPL activity in muscle (mLPL); and (4) elevated galanin (GAL) expression and peptide levels in the anterior region of the paraventricular nucleus (PVN), with no change in the arcuate nucleus. The acute 1-day or 2-h high-fat diet similarly increased circulating lipids, HADH activity and PVN GAL mRNA but stimulated rather than suppressed mLPL activity. These effects occurred in the absence of a change in total caloric intake, fat pad weights, and adipose-related measures, suggesting that they resulted more from the rise in dietary fat from 25% to 50% than from increased adiposity or hyperphagia. Moreover, PVN GAL mRNA in the different groups was consistently and positively correlated with the specific measures of TG levels and both HADH and mLPL activity, linking it to metabolic processes related to the transport and capacity for oxidation of TG in muscle, rather than adipose tissue.
Leibowitz
Sarah F
SF
Laboratory of Behavioral Neurobiology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. leibow@mail.rockefeller.edu
Dourmashkin
Jordan T
JT
Chang
Guo-Qing
GQ
Hill
James O
JO
Gayles
Ellis C
EC
Fried
Susan K
SK
Wang
Jian
J
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000273:Adipose Tissue / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001693:Biological Transport, Active / Q000187:drug effects; D001823:Body Composition / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004032:Diet; D004041:Dietary Fats / Q000494:pharmacology*; D002149:Energy Intake / Q000502:physiology; D019004:Galanin / Q000378:metabolism*; D006728:Hormones / Q000097:blood; D017403:In Situ Hybridization; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014280:Triglycerides / Q000378:metabolism*
D004041:Dietary Fats; D006728:Hormones; D014280:Triglycerides; D019004:Galanin; D015094:3-Hydroxyacyl CoA Dehydrogenases; D002950:Citrate (si)-Synthase