Abstract: Insulin resistance usually precedes the onset of type 2 diabetes. Therefore, studying factors that may influence the development of insulin resistance and their mechanisms of action is of huge importance. The aim of the present study was to investigate the effect of dietary fat type on the development of insulin resistance in relation to PPARγ activation and leptin concentration. Male Sprague–Dawley rats were assigned into maize starch-fed or fructose-fed group. The rats consumed diets containing olive oil, maize oil or sheep tallow for 10 weeks. Serum glucose, insulin and leptin concentrations were then determined. HOMA-IR was calculated as an index of insulin resistance. PPARγ activation was assessed using a PPRE-based ELISA system. Sheep tallow produced the highest HOMA-IR in the maize starch-fed group. In the fructose-fed group, rats consuming olive oil were the only rats to show significantly higher HOMA-IR and insulin concentration compared to the maize starch-fed group. Neither PPARγ activation nor leptin concentration was affected by dietary fat type. In conclusion, dietary fat type, in the maize starch-fed group, altered insulin resistance by mechanisms independent of affecting PPARγ activation or leptin concentration with sheep tallow showing a deleterious effect. [Al-Jada DN, Ahmad MN. Effect of dietary fats on the development of insulin resistance in relation to PPARγ activation and leptin concentration in rats. J Am Sci 2014;10(8):59-66]. (ISSN: 1545-1003). http://www.jofamericanscience.org. 8 Keywords: Dietary fats; PPARγ activation; Leptin; HOMA-IR; High-fructose diet; Transcription factors; Adipocytokines; Rats
Abstract:
Insulin resistance usually precedes the onset of type 2 diabetes. Therefore, studying factors that may influence the development of insulin resistance and their mechanisms of action is of huge importance. The aim of the present study was to investigate the effect of dietary fat type on the development of insulin resistance in relation to PPARγ activation and leptin concentration. Male Sprague–Dawley rats were assigned into maize starch-fed or fructose-fed group. The rats consumed diets containing olive oil, maize oil or sheep tallow for 10 weeks. Serum glucose, insulin and leptin concentrations were then determined. HOMA-IR was calculated as an index of insulin resistance. PPARγ activation was assessed using a PPRE-based ELISA system. Sheep tallow produced the highest HOMA-IR in the maize starch-fed group. In the fructose-fed group, rats consuming olive oil were the only rats to show significantly higher HOMA-IR and insulin concentration compared to the maize starch-fed group. Neither PPARγ activation nor leptin concentration was affected by dietary fat type. In conclusion, dietary fat type, in the maize starch-fed group, altered insulin resistance by mechanisms independent of affecting PPARγ activation or leptin concentration with sheep tallow showing a deleterious effect. [Al-Jada DN, Ahmad MN. Effect of dietary fats on the development of insulin resistance in relation to PPARγ activation and leptin concentration in rats. J Am Sci 2014;10(8):59-66]. (ISSN: 1545-1003). http://www.jofamericanscience.org. 8 Keywords: Dietary fats; PPARγ activation; Leptin; HOMA-IR; High-fructose diet; Transcription factors; Adipocytokines; Rats