LEPR and type 2 diabetes mellitus: From the diagnostic point of view, the most important results of the discriminant analysis allowing the selection of the parameters best differentiating the group of patients with type 2 diabetes before the implementation of the insulin therapy, as well as after a six-month period of using insulin, were obtained for the two analysed regulatory molecules such as leptin receptor, Δw(19), and adiponectin, Δw(21).