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Carbohydrate Metabolism · NEET PG Preparation Biochemistry

A 45-year-old chronic alcoholic is brought to the hospital in an unarousable state following a binge-drinking episode. He has not eaten for the past…

Practice question from Carbohydrate Metabolism (NEET PG Preparation Biochemistry), with the correct answer and a step-by-step solution.

hard · MCQ · Q-E14DEC

A 45-year-old chronic alcoholic is brought to the hospital in an unarousable state following a binge-drinking episode. He has not eaten for the past two days. Laboratory tests reveal profound hypoglycemia with an unexpectedly low level of circulating alanine and lactate, and an elevated NADH/NAD+ ratio in the liver. Which key regulatory enzyme of gluconeogenesis is primarily inhibited under these conditions?

  1. A.Pyruvate carboxylaseCorrect answer
  2. B.Phosphoenolpyruvate carboxykinase (PEPCK)
  3. C.Fructose-1,6-bisphosphatase
  4. D.Glucose-6-phosphatase

Solution

Ethanol metabolism by alcohol dehydrogenase and aldehyde dehydrogenase generates excessive NADH, increasing the hepatic NADH/NAD+ ratio. This shifts metabolic intermediates away from gluconeogenesis precursors (e.g., pyruvate is diverted to malate/lactate), impairing pyruvate carboxylase and leading to alcohol-induced hypoglycemia.

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