This conclusion is further supported by the observation that the endogenous total GLP1 concentration after the MMTT was only about one third lower than the expected GLP1 exposure during the GGI/GLP1 PD test, and furthermore, by the knowledge that the GLP1-insulin secretion dose response relationship in T2DM is linear [25]. The gene discussed is GCG; the disease is type 2 diabetes mellitus.