Hypothalamic fructose metabolism is associated with an increased desire for food intake. Altered feeding behaviors with fructose consumption are related to changing levels of which of the following metabolic intermediates?
A) acetyl-CoA
B) citrate
C) fructose 2,6-bisphosphate
D) malonyl-CoA
E) pyruvate

Question

Quizplus · Accepted Answer

Malonyl-CoA is a key metabolic intermediate that regulates feeding behavior. It is involved in the signaling pathway that affects appetite control in the hypothalamus. Changes in its levels can influence the desire for food intake.  Hypothalamic fructose metabolism bypasses rapidly depletes ATP levels resulting in increased AMP levels. The rise in AMP results in activation of AMPK which, in turn, leads to phosphorylation and inhibition of acetyl-CoA carboxylase (ACC) with the result being decreased malonyl-CoA levels in the hypothalamus. Hypothalamic malonyl-CoA is a key intermediate in the regulation of feeding behavior and overall energy balance initiated via signaling cascades within the hypothalamus. During periods when energy expenditure exceeds intake, such as during fasting, malonyl-CoA levels in the hypothalamus are low. Following food intake there is a rapid rise in hypothalamic malonyl-CoA levels. The changes in hypothalamic malonyl-CoA levels are followed quickly by changes in expression of orexigenic and anorexigenic peptides.

Hypothalamic Fructose Metabolism Is Associated with an Increased Desire for Food