A 16-year-old girl diagnosed with anorexia nervosa is brought to the emergency department after becoming very light-headed, breaking into a sweat, and developing palpitations while exercising. She exercises regularly. Her serum glucose is 40 mg/dL. The patient is given a soft drink to sip, and she feels better half an hour later. Which of the following hormones most likely triggered the sweating and palpitations the patient experienced?

**Core Concept**
The patient's symptoms of sweating, palpitations, and light-headedness are indicative of a hypoglycemic episode, triggered by an imbalance in glucose levels in the body. This is a common complication in individuals with anorexia nervosa, who often experience episodes of low blood sugar due to inadequate nutrition and excessive exercise.

**Why the Correct Answer is Right**
The hormone that most likely triggered the patient's symptoms is glucagon. Glucagon is a hormone produced by the pancreas that raises blood glucose levels by stimulating the liver to release stored glucose (glycogen) into the bloodstream. In response to the patient's low serum glucose level, glucagon was secreted to help increase blood glucose levels. This sudden increase in glucose release can cause symptoms such as sweating, palpitations, and light-headedness.

**Why Each Wrong Option is Incorrect**
**Option A:** Insulin would actually decrease blood glucose levels, making hypoglycemia worse, not better.
**Option B:** Growth hormone is not directly involved in regulating blood glucose levels in this context.
**Option C:** Epinephrine can cause symptoms of hypoglycemia, but it is not the hormone most likely responsible for triggering the patient's symptoms in this scenario.

**Clinical Pearl / High-Yield Fact**
In patients with anorexia nervosa, hypoglycemic episodes can be triggered by a variety of factors, including excessive exercise, inadequate nutrition, and the use of certain medications. It is essential for healthcare providers to recognize the signs and symptoms of hypoglycemia in these patients and take prompt action to treat the episode and prevent future occurrences.

**Correct Answer:** C. Glucagon.

✓ Correct Answer: C. Epinephrine