During which physiological state does PFK-2 reduce Fructose 2,6-bisphosphate?

In the fasting state, the body undergoes physiological changes that lead to a decrease in insulin levels and an increase in glucagon levels. These hormonal changes result in a shift in energy metabolism toward gluconeogenesis, the process by which glucose is synthesized from non-carbohydrate precursors.

Fructose 2,6-bisphosphate plays a crucial role in regulating gluconeogenesis and glycolysis. In the fasting state, the reduction in fructose 2,6-bisphosphate occurs because the activity of phosphofructokinase-2 (PFK-2) is inhibited. PFK-2 is responsible for synthesizing fructose 2,6-bisphosphate, and when it is less active, levels of this metabolite drop. This reduction favors gluconeogenesis as fructose 2,6-bisphosphate inhibits fructose 1,6-bisphosphatase, an important enzyme in gluconeogenesis. Therefore, with lower levels of fructose 2,6-bisphosphate present, gluconeogenesis becomes enhanced, allowing the body to produce glucose to maintain blood sugar levels during fasting.

In contrast, during the postprandial and fed states, when insulin is high,