Remarkably, treatment with 8-OH-DPAT significantly downregulated the expression of these enzymes in LSSC tissues, not only threefold relative to that in tissues from T1DM animals but also to levels below that observed in control animals (50–60% less, Figure 7B, Ido1: F: 32.6, p = 0.0006; Ido2: F: 19.6, p = 0.0023; Tdo: F: 29.9, p = 0.0008). This evidence concerns the gene TDO2 and type 1 diabetes mellitus.