In Zucker diabetic fatty rats representing a type 2 diabetes model and in a type 1 diabetes animal model with streptozotocin an impaired insulin secretion and signaling and an increased hepatic gene expression of CBS and BHMT representing the branch-point enzymes of C1-metabolism have been reported [47], [48], [49], [50]. The gene discussed is INS; the disease is type 2 diabetes mellitus.