Elevated serum concentrations of Kyn and its down-stream derivative, kynurenic acid (KYNA), were observed in type 2 diabetes [12] and in Zucker Fatty Rats (ZFR), an experimrntal model of MetS [13]suggesting deficiency of kynurenine-3-monooxygenase (KMO), a key enzyme of Kyn down-stream metabolism [14]. Here, KMO is linked to type 2 diabetes mellitus.