Normal distribution of body weight gain in male Sprague-Dawley rats fed a high-energy diet.
OBJECTIVE
To investigate the effect of a high-energy (HE) diet on caloric intake, body weight, and related parameters in outbred male Sprague-Dawley (SD) rats.


METHODS
Twenty-eight SD rats were fed either chow (C) for 19 weeks or HE diet for 14 weeks and then C for 5 weeks. Blood hormones and metabolites were assayed, and expression of uncoupling protein-1 and hypothalamic energy-balance-related genes were determined by Northern blotting and in situ hybridization, respectively.


RESULTS
HE rats gained body weight more rapidly than C animals with a range of weight gains, but there was no evidence that weight gain was bimodally distributed. Caloric intake was transiently elevated after introduction of the HE diet. Transfer of HE rats back to C resulted in a drop in caloric intake, but a stable body weight. In terminal analysis, two of four dissected adipose tissue depots were heavier in rats that had previously been fed HE diet. Blood leptin, insulin, glucose, and nonesterified fatty acids were not different between the groups. Uncoupling protein-1 mRNA was elevated in interscapular brown adipose tissue from HE rats. There was a trend for agouti-related peptide mRNA in the hypothalamic arcuate nucleus to be higher in HE rats.


CONCLUSIONS
Contrary to other studies of the SD rat on HE diet, body weight and other measured parameters were normally distributed. There was no segregation into two distinct populations on the basis of susceptibility to diet-induced obesity. This characteristic may be dependent on the breeding colony from which animals were sourced.
Archer
Zoe A
ZA
Division of Energy Balance and Obesity, Rowett Research Institute, Aberdeen Centre for Energy Regulation and Obesity (ACERO), Bucksburn, Aberdeen AB21 9SB, Scotland, U.K. zaa@rri.sari.ac.uk
Rayner
D Vernon
DV
Rozman
Jan
J
Klingenspor
Martin
M
Mercer
Julian G
JG
D000273:Adipose Tissue / Q000033:anatomy & histology; D002001:Adipose Tissue, Brown / Q000737:chemistry; D054369:Agouti-Related Protein; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000737:chemistry; D001786:Blood Glucose / Q000032:analysis; D002352:Carrier Proteins / Q000235:genetics; D002149:Energy Intake; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007328:Insulin / Q000097:blood; D036341:Intercellular Signaling Peptides and Proteins; D007473:Ion Channels; D020738:Leptin / Q000097:blood; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D024101:Mitochondrial Proteins; D009929:Organ Size; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D000071256:Uncoupling Protein 1; D015430:Weight Gain
D054369:Agouti-Related Protein; D001786:Blood Glucose; D002352:Carrier Proteins; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D007473:Ion Channels; D020738:Leptin; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; D012333:RNA, Messenger; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1