Unformatted text preview: Insulin Stimulation of:
-glycogen synthesis Low
Glucagon -Inhibit glycolysis
-Stimulates gluconeogenesis Enzyme- linked Membrane Receptors • Many membrane receptors consists of: – extracellular ligand- binding domain, and of – intracellular catalyGc domain • The most common catalyGc domains have the tyrosine kinase acGvity – Adds a phosphate group to itself; auto- phosphorylaGon leads to a conformaGonal change allowing binding and cataly6c phosphoryla6on of speciﬁc target proteins – Adds a phosphate group to a tyrosine in speciﬁc target proteins • Some catalyGc domains have guanylyl cyclase acGvity – Convert GTP to cGMP, a secondary messenger Receptor Tyrosine Kinases Insulin: The Hormone for Glucose Uptake and Metabolism • Insulin is a pep6de hormone produced in the pancrease by the β- cells of islets of Langerhans – Insulin is produced and released from the pancreas in response to nutrients such as glucose • ...
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