Which statement best describes insulin's effect on hepatic glucose production and glycogen storage?

• A. Inhibits hepatic gluconeogenesis and glycogenolysis; promotes glycogen synthesis and glycolysis; uses GLUT2 for glucose entry independent of insulin; promotes lipogenesis.
• B. Stimulates hepatic gluconeogenesis and glycogenolysis; reduces glycolysis; decreases lipogenesis.
• C. Insulin only affects muscle; liver is unaffected.
• D. Insulin primarily increases hepatic glucose output.

Answer: (A)

The essential idea here is how insulin shifts the liver from making glucose to storing and using it. After a meal, insulin signals liver cells to stop producing glucose and start storing it and using it for energy. It inhibits hepatic gluconeogenesis (the production of new glucose) and glycogenolysis (the breakdown of glycogen), while promoting glycogen synthesis (glycogenesis) to store glucose and glycolysis to break glucose down for use or further processing. Insulin also drives lipogenesis, turning excess glucose into fatty acids for storage.

A key detail is that the liver takes up glucose through GLUT2, a transporter whose activity isn’t driven by insulin, so glucose entry into the liver is insulin-independent, even as insulin still promotes the liver’s use and storage of that glucose.

So the statement that best matches these effects is the one describing reduced glucose production, increased glycogen storage and glycolysis, with GLUT2-mediated glucose entry independent of insulin, and promotion of lipogenesis. The other options describe the opposite effects or incorrect ideas about liver insulin action.