Within the hypothalamus, metabolism of fructose results in a significant drop in the ATP:ADP ratio. The resulting increase in AMP results in altered metabolic pathways that in turn result in an increased desire for food intake. Which of the following metabolic changes is a contributing factor to the increased feeding behaviors associated with fructose consumption?
A) decreased fatty acid synthesis
B) decreased glycolysis
C) decreased fatty acid oxidation
D) increased fatty acid oxidation
E) increased gluconeogenesis

Question

Quizplus · Accepted Answer

Metabolism of fructose in the brain exerts an orexigenic (feeding desire) effect. Hypothalamic fructose metabolism rapidly depletes ATP levels in the hypothalamus 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 [rate-limiting enzyme of fatty acid synthesis]) with the result being decreased malonyl-CoA levels in the hypothalamus. Decreased malonyl-CoA levels result in reduced inhibition of fatty acid uptake into the mitochondrial. Thus, when malonyl-CoA levels fall fat oxidation increases. This reduces the overall level of fatty acids and fatty acid esters within cells of the hypothalamus, triggering the synthesis and release of orexigenic peptides with an increased desire for food intake.

Within the Hypothalamus, Metabolism of Fructose Results in a Significant