Which of the following responsible for fasting hypoglycemia ?
**Core Concept**
Fasting hypoglycemia is a condition characterized by low blood glucose levels that occur after an overnight fast. It is often caused by an imbalance in glucose production or utilization in the body.
**Why the Correct Answer is Right**
The correct answer is **Glucagon**. Glucagon is a hormone produced by the pancreas that plays a crucial role in maintaining normal blood glucose levels. During fasting, glucagon stimulates the liver to convert stored glycogen into glucose, which is then released into the bloodstream. This process helps to maintain blood glucose levels within a normal range. In addition, glucagon also stimulates the release of glucose from stored fat (glycogenolysis) and the production of new glucose through gluconeogenesis.
**Why Each Wrong Option is Incorrect**
**Option A:** **Insulin** is incorrect because insulin lowers blood glucose levels, whereas glucagon is responsible for increasing blood glucose levels. Insulin is secreted in response to high blood glucose levels, not low.
**Option B:** **Cortisol** is incorrect because cortisol is a stress hormone that also has a role in gluconeogenesis, but it is not the primary hormone responsible for fasting hypoglycemia.
**Option D:** **Ghrelin** is incorrect because ghrelin is a hormone that stimulates appetite and increases food intake, but it is not directly involved in maintaining blood glucose levels during fasting.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that fasting hypoglycemia can be caused by a variety of factors, including pancreatic insufficiency, liver disease, and certain medications. A thorough evaluation of the patient's medical history and laboratory results is necessary to determine the underlying cause of fasting hypoglycemia.
**Correct Answer:** C. Glucagon