What is the source of gonadotropin-releasing hormone?

Options

A. Hypothalamus
B. Anterior lobe of pituitary
C. Posterior lobe of pituitary
D. Intermedeiate lobe of pituitary

Answer

To determine the source of gonadotropin-releasing hormone (GnRH), we can analyze the options provided:

1. **Hypothalamus**: The hypothalamus is a crucial gland in the endocrine system. It is responsible for the production and secretion of various releasing hormones, including gonadotropin-releasing hormone (GnRH). GnRH plays a vital role in regulating the reproductive system by stimulating the anterior pituitary gland to release gonadotropins (LH and FSH).

2. **Anterior lobe of pituitary**: The anterior lobe of the pituitary gland secretes hormones such as follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH), but it does not produce GnRH itself. Instead, it responds to GnRH from the hypothalamus.

3. **Posterior lobe of pituitary**: The posterior lobe of the pituitary gland releases hormones like oxytocin and vasopressin (ADH), but it does not produce GnRH.

4. **Intermediate lobe of pituitary**: The intermediate lobe of the pituitary is responsible for secreting melanocyte-stimulating hormone (MSH) and does not produce GnRH.

Based on this analysis, the source of gonadotropin-releasing hormone (GnRH) is the **hypothalamus**.

### Step-by-Step Solution:
1. Identify the hormone in question: Gonadotropin-releasing hormone (GnRH).
2. Review the options provided: hypothalamus, anterior lobe of pituitary, posterior lobe of pituitary, intermediate lobe of pituitary.
3. Analyze the function of each option:
- **Hypothalamus**: Produces GnRH.
- **Anterior lobe of pituitary**: Secretes hormones in response to GnRH.
- **Posterior lobe of pituitary**: Releases other hormones, not GnRH.
- **Intermediate lobe of pituitary**: Secretes MSH, not GnRH.
4. Conclude that the source of GnRH is the **hypothalamus**.