All are true about GIP (Glucose dependent insulinotropic Polypeptide) except:
C i.e. GIP inhibits GLP-1Ref: (Review article by Christensen MB, dan Med J 2016) and for option (d) diabetes, 2009 (Exogenous GIP worsens post prandial hyperglycemia in T2DM) and for option (b) Inhibition of GIP release by insulin and glucose, diabetes, 1980Explanation:GIP and GLP-1 (glucagon like peptide -1) are incretin hormones (enhance insulin secretion), also affect glucagon secretion.Secreted by enteroendocrine intestinal k cells upon nutrient stimulation.GIP gene located on chr 17q, structurally related to secretin family. Binds to G protein coupled receptorsGIP acts as a bifunctional blood glucose stabilizing hormone, means it has effects on insulin and glucagon responses highly dependent on blood glucose levels.Other OptionsOption (d)GIP has short lived insulinotropic effect in T2DM, it worsens postprandial hyperglycemia most likely through suppressive effect on GLP 1.Option (b)huInhibition of GIP release by insulin and glucose stimulation.Option (a) and (c)GIP enhances postprandial glucagon and GLP 1 suppresses it.Both share common properties as incretins, but they also possess different biological characteristics.Sulfonylureas and incretins acts synergistically to stimulate insulin secretion, so combination drugs potentially cause hypoglycemia.GIP has many additional actions than insulinotropic activity like:Promote growth of pancreatic beta cell.Stimulate adipogenesis.Increase expression of anti-apoptotic Bcl-2 (resulting in reduced beta cell death).Inhibits gastric acid and pepsin release.Involves in number of c AMP dependent intracellular pathways.
GIP stimulates glucagon release
GIP is inhibited by insulin
GIP inhibits GLP-1
GIP in T2DM worsens post prandial hyperglycemia
Carbohydrates