DPP4 and diabetes mellitus: To elucidate the effects of diabetic and non-diabetic plasma on ICAM, FMO3, and DPP4 protein expression in the liver of diabetes, plasma from Leprdb/db and Lepr+/+ mice was injected into the adipose tissue of Leprdb/db mice, and the protein expression of ICAM, DPP4, and FMO3 in the liver was examined.