Which of the following statements is correct in relation to the endocrine system.

Options

A. Non-nutrient chemicals produced by the body in trace amount that act as intercellular messenger are known as hormones.
B. Releasing and inhibitory hormones are produced by the pituitary gland.
C. Adenohypophysis is under direct neu- ral regulation of the hypothalamus.
D. Organs in the body like gastrointes- tinal tract, heart, kidney and liver do not produce any hormone

Answer

To solve the question regarding the correct statement in relation to the endocrine system, we will analyze each option provided:

1. **Option A**: "Non-nutrient chemicals produced by the body in trace amounts that act as intercellular messengers are known as hormones."
- **Analysis**: This statement is correct. Hormones are indeed non-nutrient chemicals produced by the body in very small amounts, and they function as chemical messengers that facilitate communication between different organs and tissues.

2. **Option B**: "Releasing and inhibitory hormones are produced by the pituitary gland."
- **Analysis**: This statement is incorrect. Releasing and inhibitory hormones are actually produced by the hypothalamus, not the pituitary gland. The pituitary gland responds to these hormones but does not produce them.

3. **Option C**: "Adenohypophysis is under direct neural regulation of hypothalamus."
- **Analysis**: This statement is also incorrect. The adenohypophysis (anterior pituitary gland) is regulated by releasing hormones from the hypothalamus, but this regulation is not direct neural control; it is hormonal.

4. **Option D**: "Organs in the body like gastrointestinal tract, heart, kidney, and liver don't produce any hormone."
- **Analysis**: This statement is incorrect. The gastrointestinal tract produces hormones such as gastrin, the heart produces atrial natriuretic factor (ANF), the kidneys produce erythropoietin, and the liver produces angiotensinogen. Therefore, these organs do produce hormones.

Based on the analysis of each option, the correct answer is **Option A**.

### Summary of the Solution:
- **Correct Statement**: Non-nutrient chemicals produced by the body in trace amounts that act as intercellular messengers are known as hormones (Option A).