Which of the following is NOT increased by the action of insulin?

Insulin is a key hormone in regulating glucose metabolism and promoting the storage of nutrients. It primarily functions to lower blood glucose levels by facilitating the uptake of glucose by cells, especially in muscle and fat tissues, and promoting anabolic processes.

Gluconeogenesis is the process by which glucose is produced from non-carbohydrate sources, primarily occurring in the liver. Insulin acts to inhibit gluconeogenesis, thereby preventing the liver from producing and releasing glucose into the bloodstream when blood sugar levels are high. This is crucial for maintaining glucose homeostasis, as it helps to prevent further increases in blood sugar levels when they are already elevated.

In contrast, lipid synthesis and glycogenesis are processes that are stimulated by insulin. Insulin promotes the conversion of glucose to fat in adipose tissue (lipid synthesis) and aids in the storage of glucose as glycogen in the liver and muscle tissues (glycogenesis). Additionally, insulin enhances the uptake of glucose into cells, thereby facilitating its utilization for energy or storage.

Understanding the role of insulin in these metabolic pathways clarifies why gluconeogenesis is the correct response as the process that is not increased by insulin's action.