What is the mechanism of action of thiazolidinediones in diabetes management?

• A. PPAR-γ agonists that improve peripheral insulin sensitivity
• B. Inhibit hepatic glucose production only
• C. Increase insulin secretion from beta cells
• D. Block glucose absorption in intestine

Answer: (A)

Thiazolidinediones work by activating PPAR-γ, a nuclear receptor that governs the transcription of genes involved in glucose and lipid metabolism. This activation improves insulin sensitivity in key tissues—especially adipose tissue and skeletal muscle, with a beneficial effect in the liver as well. As insulin sensitivity rises, these tissues respond more effectively to insulin, leading to greater glucose uptake by muscle and a reduction in hepatic glucose production, which lowers blood glucose levels. They do not stimulate insulin release from beta cells, nor do they act by blocking intestinal glucose absorption. They primarily enhance insulin action rather than insulin secretion.