Fatty acid synthase and adipsin mRNA levels in obese and lean JCR:LA-cp rats: effect of diet.
In Sprague-Dawley rats, fatty acid synthase (FAS) activity is suppressed by dietary fat. To test the hypothesis that a defect in regulation of de novo fatty acid synthesis exists in massive obesity, we investigated the effect of diet on FAS mRNA levels in genetically obese JCR:LA-corpulent (cp) rats. We also determined levels of mRNA encoding adipsin, a fat cell-derived protein possibly associated with lipid metabolism. Hepatic FAS mRNA levels were elevated five-fold in obese compared to lean cp rats and were unsuppressed by dietary fat. Dietary sucrose increased FAS mRNA levels in lean cp rats, but, in contrast to Sprague-Dawley rats, little deposition of lipid resulted. Adipsin mRNA levels were fivefold lower in obese cp and Sprague-Dawley rats than in lean cp rats and were unaffected by diet. We conclude that exaggerated de novo fatty acid synthesis may play a major role in the pathogenesis of obesity in obese JCR:LA-corpulent rats.
Shillabeer
G
G
Department of Medicine, University of Calgary, Alberta, Canada.
Hornford
J
J
Forden
J M
JM
Wong
N C
NC
Russell
J C
JC
Lau
D C
DC
D000273:Adipose Tissue / Q000201:enzymology; D000818:Animals; D001835:Body Weight; D011416:Complement Factor D; D004032:Diet; D064429:Fatty Acid Synthases / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008297:Male; D009765:Obesity / Q000378:metabolism*; D009929:Organ Size; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D005993:Glycerolphosphate Dehydrogenase; D064429:Fatty Acid Synthases; D012697:Serine Endopeptidases; D011416:Complement Factor D