Lipogenic enzyme activities and glucose uptake in fat tissue of dyslipemic, insulin-resistant rats: effects of fish oil.

Objective: The purposes of the present work were twofold: (1) investigate same mechanisms involved in the development of fat cell hypertrophy in the experimental model of dyslipidemia and whole-body insulin resistance induced in rats chronically fed a sucrose-rich diet (SRD); and (2) analyze the possible beneficial effect of fish oil on these mechanisms.

Methods: For 6 mo, male Wistar rats received a sucrose-rich diet (62.5% w/w sucrose, 8% corn oil) or a control diet in which sucrose was replaced by starch. After this period, the sucrose-fed animals were divided randomly into two groups: the first one continued with the same diet up to 8 mo and the second one received the same diet, but with corn oil replaced by 7% fish oil+1 % corn oil. Rats were fed with this diet for the next 2 mo.

Results: Although an enlarged fat cell lipolysis and an impaired insulin-stimulated glucose uptake were present in the fat cells of SRD-fed rats, an increase of several key enzymes of the novo lipogenesis could be one of the possible mechanisms involved in visceral adiposity. The addition of dietary fish oil restored or improved the above abnormalities.

Conclusion: This study shows possible mechanisms conditioning the influence of nutrients on the development and management of dyslipidemia, insulin sensitivity, and fat cell accretion, all abnormalities present in the metabolic syndrome.