Differences in adipocyte long chain fatty acid uptake in Osborne-Mendel and S5B/Pl rats in response to high-fat diets.
OBJECTIVE
To determine whether strain differences in adipocyte uptake of long chain fatty acids (LCFAs) contribute to differences in weight gain by Osborne-Mendel (OM) and S5B/Pl rats (S) fed a high-fat diet (HFD).


METHODS
Ninety-four adult (12-14-week old) male OM and S rats.


METHODS
Body weight; epididymal fat pad weight; adipocyte size, number, LCFA uptake kinetics; and plasma insulin and leptin during administration of HFD or chow diets (CDs).


RESULTS
In both strains, rate of weight gain (RWG) was greater on an HFD than a CD; RWG on an HFD was greater, overall, in OM than S. A significant RWG increase occurred on days 1 and 2 in both strains. It was normalized in S by days 6-9 but persisted at least till day 14 in OM. RWGs were significantly correlated (P<0.001) with the V(max) for saturable adipocyte LCFA uptake (V(max)). In S, an increase in V(max) on day 1 returned to baseline by day 7 and was correlated with both plasma insulin and leptin levels throughout. In OM, a greater increase in V(max) was evident by day 2, and persisted for at least 14 days, during which both insulin and leptin levels remained elevated. Growth in epididymal fat pads on the HFD correlated with body weight, reflecting hypertrophy in OM and both hypertrophy and hyperplasia in S.


CONCLUSIONS
(a) Changes in V(max) contribute significantly to changes in RWG on HFDs. (b) There are important strain differences in circulating insulin and leptin responses to an HFD. (c) Both insulin and leptin responses to an HFD are closely correlated with V(max) of adipocyte fatty acid uptake in S animals, but suggest early onset of insulin resistance in OM. Thus, differences in hormonal regulation of adipocyte LCFA uptake may underlie the different responses of OM and S to HFD.
Petrescu
O
O
Division of Liver Diseases, Department of Medicine, Mount Sinai School of Medicine, New York, NY, USA.
Cheema
A F
AF
Fan
X
X
Bradbury
M W
MW
Berk
P D
PD
D017667:Adipocytes / Q000378:metabolism*; D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003066:Coenzyme A Ligases / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage; D007328:Insulin / Q000097:blood; D037102:Lectins / Q000097:blood; D008297:Male; D024101:Mitochondrial Proteins; D051381:Rats; D013045:Species Specificity; D015430:Weight Gain / Q000502:physiology*
D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin; D037102:Lectins; D024101:Mitochondrial Proteins; D003066:Coenzyme A Ligases; C508147:Acsl5 protein, rat