If you have not eaten for several hours, which hormone would you expect to be in relatively high concentrations in your blood?

• A. Insulin and cholecystokinin.
• B. Glucagon and ghrelin.
• C. Glucagon and cholecystokinin.
• D. Insulin and ghrelin.

Answer: (B)

Verified step by step guidance

1. Understand the physiological context: When you have not eaten for several hours, your body enters a fasting state. During this state, certain hormones are released to maintain blood glucose levels and signal hunger.
2. Identify the role of glucagon: Glucagon is a hormone secreted by the pancreas when blood glucose levels are low. It stimulates the liver to break down glycogen into glucose (glycogenolysis) and release it into the bloodstream to maintain energy levels.
3. Identify the role of ghrelin: Ghrelin is known as the 'hunger hormone.' It is secreted by the stomach when it is empty, signaling the brain to stimulate appetite and prepare the body for food intake.
4. Eliminate incorrect options: Insulin is released in response to high blood glucose levels, typically after eating, so it would not be elevated during fasting. Cholecystokinin (CCK) is released in response to food in the small intestine, particularly fats and proteins, and is not relevant during fasting.
5. Conclude the correct answer: Based on the roles of the hormones, the correct answer is 'Glucagon and ghrelin,' as these are the hormones expected to be in relatively high concentrations during a fasting state.