Which of the hormones possesses an effect which is antagonistic to insulin in context of carbohydrate metabolism?

Options

A. Cortisol
B. Calcitonin
C. Oxytocin
D. Aldosterone

Explanation

**Step-by-Step Solution:**

1. **Understanding Insulin's Role**: Insulin is a hormone produced by the beta cells of the pancreas. Its primary function in carbohydrate metabolism is to lower blood glucose levels. It does this by promoting the uptake of glucose by cells, particularly in the liver (hepatocytes) and muscle tissues, and converting glucose into glycogen for storage.

2. **Identifying the Opposite Effect**: Since the question asks for a hormone that has an antagonistic effect to insulin, we need to look for a hormone that raises blood glucose levels, counteracting insulin's action.

3. **Exploring Other Hormones**: Among the hormones involved in carbohydrate metabolism, cortisol is a glucocorticoid hormone secreted by the adrenal cortex. It plays a role in increasing blood glucose levels through a process called glycogenolysis, where glycogen is broken down into glucose.

4. **Conclusion**: Given that cortisol increases blood glucose levels (hyperglycemia) and insulin decreases them (hypoglycemia), cortisol is the hormone that possesses an effect which is antagonistic to insulin in the context of carbohydrate metabolism.

5. **Final Answer**: The hormone that has an antagonistic effect to insulin in carbohydrate metabolism is **cortisol**.

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