MCQ Detailed View

The regulation of blood glucose (blood sugar) levels is one of the most critical functions in human physiology. Glucose is the body’s primary source of energy, and maintaining its level within a narrow range is essential for survival. Multiple hormones and nutrients influence blood glucose.

Carbohydrates are the main dietary source of glucose. After digestion, carbohydrates are broken down into simple sugars such as glucose, which are absorbed into the bloodstream. This leads to a rise in blood glucose levels, especially after meals.

Epinephrine (adrenaline), secreted by the adrenal glands during stress or “fight-or-flight” situations, increases blood glucose. It does this by stimulating glycogenolysis (breaking down glycogen stored in the liver into glucose) and gluconeogenesis (formation of glucose from non-carbohydrate sources). This ensures the body has enough energy in emergencies.

Cholesterol, although not a direct source of glucose, is a lipid that plays a role in overall metabolism. It doesn’t provide glucose directly but is associated with metabolic processes that can influence energy balance and may indirectly affect glucose regulation.

Insulin, however, works in the opposite direction. It is a hormone produced by the pancreas (beta cells of the islets of Langerhans). Its primary function is to lower blood glucose levels by facilitating the uptake of glucose into cells (especially muscle and fat cells) and promoting its storage as glycogen in the liver. Without insulin, glucose remains in the bloodstream, leading to hyperglycemia (high blood sugar).

This is why diabetes mellitus results from either lack of insulin (Type 1 diabetes) or insulin resistance (Type 2 diabetes). In both conditions, blood glucose levels remain high because insulin action is impaired.

✅ Key Facts Recap

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  Carbohydrates → Raise glucose

  
  


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  Epinephrine → Raises glucose (stress hormone)

  
  


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  Cholesterol → Indirect role in metabolism

  
  


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  Insulin → Lowers glucose (exception here)

  
  

Thus, the correct answer is Insulin, as it does not raise blood glucose but instead lowers it.