UCP3 and Impaired glucose tolerance: These data are in good accordance with clinical observations reporting that (i) a 50% reduction of UCP3 protein in human SkM is correlated with the incidence of T2DM (Schrauwen et al., 2001); and (ii) in humans, UCP3 protein levels are reduced in the pre-diabetic state of impaired glucose tolerance (Schrauwen and Hesselink, 2004a; Mensink et al., 2007).