A 14-year-old boy is brought to the emergency department due to excessive urination and thirst. He has lost 4.5 kg (10 lb) in the last 3 weeks. The patient has no past medical problems. His father has type 1 diabetes mellitus. Physical examination shows dry mucous membranes. Laboratory studies reveal blood glucose of 455 mg/dL, normal anion gap, and hemoglobin A1c of 11.3%. The patient is diagnosed with type 1 diabetes, and treatment with insulin is initiated. In addition to lowering blood glucose, insulin increases glycogen synthesis in hepatocytes. Activation of which of the following molecules most likely promotes this metabolic effect?

Question

A 14-year-old boy is brought to the emergency department due to excessive urination and thirst.  He has lost 4.5 kg (10 lb) in the last 3 weeks.  The patient has no past medical problems.  His father has type 1 diabetes mellitus.  Physical examination shows dry mucous membranes.  Laboratory studies reveal blood glucose of 455 mg/dL, normal anion gap, and hemoglobin A1c of 11.3%.  The patient is diagnosed with type 1 diabetes, and treatment with insulin is initiated.  In addition to lowering blood glucose, insulin increases glycogen synthesis in hepatocytes.  Activation of which of the following molecules most likely promotes this metabolic effect?

Quizplus · Accepted Answer

Eductional Objective: Insulin is an anabolic hormone that acts via receptor tyrosine kinase signaling to increase the synthesis of glycogen, proteins, fatty acids, and nucleic acids.  Tyrosine kinase/phosphatidylinositol-3-kinase stimulation promotes glycogen synthesis by activating protein phosphatase, an enzyme that dephosphorylates (activates) glycogen synthase.

A 14-Year-Old Boy Is Brought to the Emergency Department Due