Leptin drives fat distribution during diet-induced obesity in mice.
OBJECTIVE
Desensitization of leptin receptors is a process that specifically occurs in some tissues. We have hypothesized that during the development of obesity tissue lipids would increase gradually in particular organs depending on leptin responsiveness. Our aim was to establish a relationship between leptin resistance and lipid deposition by using a model of diet-induced obesity (DIO) and we have characterized, in mice undergoing a dietary treatment with a high-fat (HF) diet, the evolution of lipid content and leptin responsiveness in white adipose tissue and liver.


METHODS
Four-week-old male C57BL/6J mice were divided into two groups and assigned either to a low-fat or to a high-fat diet. Dietary treatment lasted 8, 20 or 32 weeks. The last day animals received 1mg/kg leptin and then tissues were weighed and processed for Western-blotting and lipid determination.


RESULTS
We observed an initial increase of the relative weight of adipose pads that was blunted after 32-week HF. In contrast, liver size exhibited an initial decrease followed by a progressive increase, which was coincident with the increase of hepatic triglycerides and with the impairment of leptin receptor signalling.


CONCLUSIONS
Our data show that leptin resistance within white adipose tissue does not deal with an increase of the size of adipose pads and suggest that consequences of leptin resistance, in terms of fat accumulation, are tissue-dependent.
Departamento de Ciencias Farmacéuticas y de la Alimentación, Facultad de Farmacia, Universidad CEU-San Pablo, Madrid, Spain.
Rocío
R
Guzmán-Ruiz
Paula
P
Stucchi
Maria Pilar
MP
Ramos
Julio
J
Sevillano
Beatriz
B
Somoza
Marisol
M
Fernández-Alfonso
Mariano
M
Ruiz-Gayo
D000818:Animals; D050218:Body Fat Distribution; D059305:Diet, High-Fat; D020738:Leptin / Q000502:physiology*; D050356:Lipid Metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000378:metabolism*; D054411:Receptors, Leptin / Q000502:physiology*
D020738:Leptin; D054411:Receptors, Leptin