Question

A patient had dinner at 8 PM in the night and dose his blood sugar test at 7 AM in the morning. What is the major source of glucose

• A. Muscle Glycogen
• B. Liver Glycogen
• C. Gluconeogenesis
• D. Dietary Carbohydrate

Answer 1

The Correct Option is B

The patient fasted for 11 hours (8 PM dinner to 7 AM test). This falls in Fasting Stage I (4-16 hours).

Sources of blood glucose by fasting duration:
- $0\text{-}4$ hrs (Fed state): Dietary carbohydrates
- $4\text{-}16$ hrs (Fasting Stage I): Liver glycogen (glycogenolysis)
- $16\text{-}48$ hrs (Fasting Stage II/III/IV): Gluconeogenesis (liver glycogen exhausted by ~16 hrs)

Why not muscle glycogen? Muscle lacks glucose-6-phosphatase, so glycogen breakdown in muscle produces glucose-6-phosphate which enters glycolysis locally -- it cannot be exported as free glucose to raise blood sugar.

Why not dietary carbohydrate? The patient has been fasting for 11 hours -- all absorbed dietary glucose from dinner has already been utilized.

Why not gluconeogenesis? That takes over after 16+ hours of fasting.
\[\boxed{\text{Liver Glycogen}}\]