How many of the following hormones are synthesised by the hypothalamus ?
(I) growth hormone releasing hormone
(II) prolactin inhibitory hormone
(III) Thyroid stimulating hormone
(IV) aldosterone
(V) luteinizing hormone
(VI) follicle stimulating hormone

Options

A. Two
B. Three
C. Six
D. One

Answer

To determine how many of the listed hormones are synthesized by the hypothalamus, we will analyze each hormone one by one:

1. **Growth Hormone Releasing Hormone (GHRH)**:
- This hormone is synthesized by the hypothalamus. Its primary function is to stimulate the anterior pituitary gland to release growth hormone (GH).

2. **Prolactin Inhibitory Hormone (PIH)**:
- This hormone is also synthesized by the hypothalamus. It inhibits the secretion of prolactin from the anterior pituitary gland.

3. **Thyroid Stimulating Hormone (TSH)**:
- TSH is not synthesized by the hypothalamus; it is produced by the anterior pituitary gland. TSH stimulates the thyroid gland to produce thyroid hormones.

4. **Aldosterone**:
- Aldosterone is not synthesized by the hypothalamus. It is produced by the adrenal cortex, specifically in the zona glomerulosa, and plays a role in regulating sodium and potassium levels.

5. **Luteinizing Hormone (LH)**:
- LH is not synthesized by the hypothalamus; it is produced by the anterior pituitary gland. LH is involved in regulating the reproductive system.

6. **Follicle Stimulating Hormone (FSH)**:
- FSH is also not synthesized by the hypothalamus. Like LH, it is produced by the anterior pituitary gland and is important for reproductive functions.

Now, let's summarize the hormones synthesized by the hypothalamus:
- GHRH: Yes
- PIH: Yes
- TSH: No
- Aldosterone: No
- LH: No
- FSH: No

**Conclusion**: The hormones synthesized by the hypothalamus are GHRH and PIH. Therefore, the total number of hormones synthesized by the hypothalamus is **2**.

### Final Answer: 2

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