Time course of liver lipid infiltration in ovariectomized rats: impact of a high-fat diet.
OBJECTIVE
The present study was undertaken to determine the time course of liver lipid infiltration in ovariectomized (Ovx) rats and the impact of high-fat (HF; 42% kJ) feeding on this response.


METHODS
In a first step, Ovx rats were compared to Sham-operated (Sham) and Ovx rats supplemented with 17beta-estradiol (OvxE2) to evaluate the effect of estrogen removal. In a second time, Ovx rats fed a HF diet (OvxHf) were compared with normally fed Ovx rats. Animals were killed after 3, 8, and 13 weeks of their respective treatment (n=8 rats/group). We measured liver triacylglycerol (TAG) content, fat pad mass, and several other plasma parameters.


RESULTS
Ovariectomy resulted in the typical increase in energy intake and body weight. Liver TAG accumulation was 35, 43, and 99% higher in Ovx than in Sham rats after 3, 8, and 13 weeks, respectively. The ovariectomy-induced liver lipid infiltration was completely prevented by estrogen replacement. On the opposite, plasma TAG concentrations were lower in Ovx than in Sham and OvxE2 rats. HF feeding in Ovx rats resulted in a significant (P<0.05; 38 versus 22 mg/g at 13-week) accumulation of fat in liver as compared to normally fed Ovx rats.


CONCLUSIONS
Ovariectomy results in a progressive accumulation of fat in liver over a 13-week period. In addition, HF feeding in Ovx rats lead to an even more severe liver lipid infiltration. These data indicate that the absence of estrogens in rat favours fat accretion in liver, which is highly amplified by a HF diet.
Paquette
Amélie
A
Department of kinesiology, University of Montreal, CP 6128, Succ. Centre-Ville, Montreal, Quebec, Canada H3C 3J7. amelie.paquette@umontreal.ca
Shinoda
Motoo
M
Rabasa Lhoret
Rémi
R
Prud'homme
Denis
D
Lavoie
Jean-Marc
JM
D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001786:Blood Glucose; D001823:Body Composition; D004041:Dietary Fats / Q000008:administration & dosage* / Q000097:blood; D015914:Estrogen Replacement Therapy; D005234:Fatty Liver / Q000378:metabolism*; D005260:Female; D005990:Glycerol / Q000097:blood; D007328:Insulin / Q000097:blood; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014280:Triglycerides / Q000378:metabolism
D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin; D014280:Triglycerides; D005990:Glycerol