Mice and rats are much more widely studied than gerbils, and at this time, mice have the advantage of being more amenable to genetic manipulation. Your final selection of a model should be tailored to your specific scientific question. For instance, a model that might be good for studying effects of insulin resistance on cardiac function may be less well suited to studying the relationship between insulin resistance and adipose tissue inflammation. In general, ad lib feeding of high fat or high fat/high sucrose diets to wild type C57Bl mice is one of the most well-established models of high fat diet-induced insulin resistance, obesity, and hyperglycemia. As C57Bl6 mice age on these diets, some will develop diabetes, but probably not as predictably as the gerbil model referred to by Juan Bueno. There are some caveats to high fat feeding: in particular, it will drive down the respiratory quotient and force induction of gene regulatory programs that regulate storage and detoxification of lipids in different tissues. As such, it may not be the best model for depicting the sort of dietary obesity/insulin resistance changes we see in human subjects, where excess carbohydrate intake often parallels excess fat intake. If you are only interested in insulin resistance itself, then feeding high fat diet to FVBn mice starting at weaning can induce insulin resistance very rapidly (within 3 weeks); this is an especially useful model for studying insulin resistance in muscle. Of course, every model has its limitations/strengths; so, again, I would try to tailor your model to your question.
Dear Kumar the gerbil Psammomys obesus (sand rat) is a model of nutritionally induced type 2 diabetes. Psammomys obesus are prone to develop hyperglycemia,
hyperinsulinemia, and obesity when fed a high-energy (HE) diet. Psammomys
express four different phenotypic stages: stage A—normoinsulinemia and normoglycemia; stage B—hyperinsulinemia but normoglycemia; stage C—hyperinsulinemia and hyperglycemia; and stage D—hypoinsulinemia and hyperglycemia as a result of loss of insulin secretion capacity.
Animal models of diabetes : frontiers in research / editor, Eleazar Shafrir. -- 2nd
Mice and rats are much more widely studied than gerbils, and at this time, mice have the advantage of being more amenable to genetic manipulation. Your final selection of a model should be tailored to your specific scientific question. For instance, a model that might be good for studying effects of insulin resistance on cardiac function may be less well suited to studying the relationship between insulin resistance and adipose tissue inflammation. In general, ad lib feeding of high fat or high fat/high sucrose diets to wild type C57Bl mice is one of the most well-established models of high fat diet-induced insulin resistance, obesity, and hyperglycemia. As C57Bl6 mice age on these diets, some will develop diabetes, but probably not as predictably as the gerbil model referred to by Juan Bueno. There are some caveats to high fat feeding: in particular, it will drive down the respiratory quotient and force induction of gene regulatory programs that regulate storage and detoxification of lipids in different tissues. As such, it may not be the best model for depicting the sort of dietary obesity/insulin resistance changes we see in human subjects, where excess carbohydrate intake often parallels excess fat intake. If you are only interested in insulin resistance itself, then feeding high fat diet to FVBn mice starting at weaning can induce insulin resistance very rapidly (within 3 weeks); this is an especially useful model for studying insulin resistance in muscle. Of course, every model has its limitations/strengths; so, again, I would try to tailor your model to your question.
C57BL/6J is indeed good model. As far as from my experiences, C57BL/6J gives me higher blood glucose during the GTT compare with other mice. This is good for creation of diabetes model by feeding. We also can buy DIO (diet induced obese) mice using C57BL/6J. About rat, I agree with Dr. Bueno that has already mentioned using sand rat. But I also can tell you one thing, Wistar gives higher blood glucose than SD during the GTT given same amount of glucose. So I guess the strain of the mouse and rat is important....