Effects of 2 G on adiposity, leptin, lipoprotein lipase, and uncoupling protein-1 in lean and obese Zucker rats.
Male Zucker rats were exposed to 2 G for 8 wk to test the hypothesis that the leptin regulatory pathway contributes to recovery from effects of 2 G on feeding, growth, and nutrient partitioning. After initial hypophagia, body mass-independent food intake of the lean rats exposed to 2 G surpassed that of the lean rats maintained at 1 G, but food intake of the obese rats exposed to 2 G remained low. After 8 wk at 2 G, body mass and carcass fat were less in both genotypes. Leptin and percent fat were lower in lean rats exposed to 2 G vs. 1 G but did not differ in obese rats exposed to 2 G vs. 1 G. Although exposure to 2 G did not alter uncoupling protein-1 levels, it did elicit white fat pad-specific changes in lipoprotein lipase activity in obese but not lean rats. We conclude that 2 G affects both genotypes but that the lean Zucker rats recover their food intake and growth rate and retain "normal" lipoprotein lipase activity to a greater degree than do the obese rats, emphasizing the importance of a functional leptin regulatory pathway in this acclimation.
Warren
L E
LE
Section of Neurobiology, Physiology, and Behavior, Division of Biological Sciences, University of California, Davis, California 95616-8519, USA.
Horwitz
B A
BA
Hamilton
J S
JS
Fuller
C A
CA
D002001:Adipose Tissue, Brown / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D002352:Carrier Proteins / Q000378:metabolism*; D002498:Centrifugation; D004435:Eating; D006112:Gravitation; D007473:Ion Channels; D020738:Leptin / Q000097:blood*; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D024101:Mitochondrial Proteins; D009765:Obesity / Q000378:metabolism*; D051381:Rats; D011924:Rats, Zucker; D013851:Thinness / Q000378:metabolism*; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D007473:Ion Channels; D020738:Leptin; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D008071:Lipoprotein Lipase