Melatonin does not control

Options

A. Diurnal rhythm of body
B. Metabolism
C. Gonadotrophic effect
D. Pigmentation

Answer

**Step-by-Step Solution:**

1. **Understand Melatonin's Function**: Melatonin is a hormone produced by the pineal gland, which is located in the forebrain. It plays a crucial role in regulating various physiological processes in the body.

2. **Identify Key Functions of Melatonin**:
- **Diurnal Rhythm**: Melatonin is known to regulate the sleep-wake cycle, also referred to as the diurnal rhythm. It helps maintain the body's circadian rhythms.
- **Metabolism**: Melatonin influences metabolic processes in the body.
- **Pigmentation**: Melatonin also plays a role in controlling pigmentation in the skin.
- **Gonadotropic Effect**: This refers to the effects related to the stimulation of the gonads (ovaries and testes). These effects are primarily regulated by gonadotropin-releasing hormone (GnRH) and not directly by melatonin.

3. **Analyze the Options**:
- **Option A (Diurnal Rhythm)**: Melatonin does control this function, so this option is incorrect in the context of the question.
- **Option B (Metabolism)**: Melatonin influences metabolism, making this option also incorrect.
- **Option C (Gonadotropic Effect)**: This is the correct answer because melatonin does not control gonadotropic effects; these are regulated by other hormones.
- **Option D (Pigmentation)**: Melatonin does control pigmentation, so this option is incorrect.

4. **Conclusion**: Based on the analysis, the correct answer to the question "Melatonin does not control" is **Option C: Gonadotropic Effect**.

---