GIP and type 2 diabetes mellitus: We surmise that action by GIP is not the main mediator of our protective effect on olanzapine-induced metabolic dysfunction because metabolically compromised individuals have a reduced insulinotropic response to GIP but not GLP1 (Nauck et al., 1993), (Mentis et al., 2011) and GIP is a stimulator of glucagon secretion even during hyperglycemia in individuals with type 2 diabetes (Mentis et al., 2011).