PPARG and obesity due to melanocortin 4 receptor deficiency: In the same study, however, rosiglitazone treatment did not alter total serum T. Compared with the above findings the data in our study allow for differentiation of diabetes steroidogenic effects (ZDF-untreated versus lean nondiabetic rats) from those of PPARγ activation (ZDF-treated versus ZDF-untreated rats) but does not permit a way for separation of obesity effects from those of diabetes.