Further examination of the mechanism whereby GABA tea ameliorates the neurodegenerative symptoms of diabetes in the brain of STZ-induced DM rats revealed that blood glucose levels increase in STZ-induced diabetes rats and improvement of hyperglycemia is achieved by deactivation of the cortical Fas ligand, Fas-associated death domain protein (FADD), caspase-8, Bid, and t-Bid levels—all of which increased following 4 weeks of STZ-induced diabetes. The gene discussed is FADD; the disease is Hyperglycemia.