Which class of medications acts directly on the beta cells to inhibit glucose-dependent insulin release?

The correct class of medications that acts directly on the beta cells to inhibit glucose-dependent insulin release is calcium-channel blockers. While primarily used in the treatment of hypertension and certain cardiac conditions, calcium-channel blockers can influence insulin secretion. They modulate the influx of calcium ions into beta cells, which are crucial for the process of insulin release in response to glucose levels. By inhibiting this calcium influx, these medications can reduce insulin secretion in a glucose-dependent manner, providing a unique mechanism of action among diabetes treatments.

Other classes of medications listed, such as alpha-glucosidase inhibitors, thiazolidinediones, and biguanides, work through different mechanisms. Alpha-glucosidase inhibitors primarily delay carbohydrate absorption in the intestine, thiazolidinediones act by enhancing insulin sensitivity in peripheral tissues, and biguanides, such as metformin, primarily reduce hepatic glucose production and increase insulin sensitivity. Each of these classes contributes to diabetes management but does not directly inhibit glucose-dependent insulin release from beta cells.