However, SD pups present a metabolic profile similar to that of pups with type 1 diabetes mellitus (T1DM), with extremely low insulin secretion, leading to severe growth retardation, a catabolic status, underdeveloped endocrine glands, oxidation, low gastrointestinal-anorexigenic signals, and high non-operative serum leptin levels. Here, LEP is linked to type 1 diabetes mellitus.