Furthermore, the combination of diabetes and HgCl2 for 45 days significantly increased TNF-alpha levels in both the hippocampus and prefrontal cortex compared to normoglycemic rats treated with HgCl2 (P = 0.000 for both) and untreated diabetic rats (P = 0.000 and P = 0.007, respectively). The gene discussed is TNF; the disease is diabetes mellitus.