We investigated seven metabolically active tissues consisting of liver, muscle, intestine (ileum), brain, pancreas, epididymal fat, and subcutaneous fat from four different mouse strains commonly used in diabetes research; leptin receptor-deficient mice C57bl/KS-Leprdb/Leprdb (DB) versus C57bl/KS-Leprdb/+ (WT), and C57bl/6J mice fed a low-fat diet (LF) or high-fat diet (HF)26. The gene discussed is LEPR; the disease is diabetes mellitus.