Obesity has increased dramatically in the world A Explain ho

Obesity has increased dramatically in the world. A) Explain how digestion of excess fructose can lead to increased plasma triglycerides. In your discussion include pathway regulation. B) Compare a healthy person metabolizing fructose to a patient with hereditary fructose intolerance.

Solution

Answer:

Digestion of excess fructose can lead to increased plasma glycerieds. In the hamster, a high-fructose diet leads to an increase in plasma triglyceride concentrations. These triglycerides, present in the circulation under the form of chylomicrons, were shown to originate from fructose conversion into fatty acids within the enterocyte (intestinal de novo lipogenesis), with subsequent association with apoB-48 to be released as chylomicrons. Whether a similar pathway is active in humans and other mammals remains however unknown.

Subsequent steps of fructose metabolism have been described in full detail elsewhere and are only briefly outlined here. Fructose-1-P is further metabolized into triose-P through the action of aldolase B. Inherited deficiency of aldolase B is a rare condition leading to hereditary fructose intolerance, characterized by the occurrence of hypoglycemia upon exposure to dietary fructose and by the development of liver steatosis and cirrhosis.