Which one of the given hormones is secreted from hypothalamus?

The correct answer is Option (3) → GnRH

The hypothalamus controls the reproductive hormones. At puberty it increases the secretion of gonadotropin releasing hormone (GnRH). GnRH acts on the anterior pituitary, which then releases LH and FSH.

Option (1) Insulin — Incorrect. Insulin is secreted by the beta cells of the pancreas and lowers blood sugar.

Option (2) TSH — Incorrect. Thyroid stimulating hormone comes from the anterior pituitary.

Option (3) GnRH — Correct. GnRH (gonadotropin releasing hormone) is secreted by the hypothalamus. It acts on the anterior pituitary, which then releases the gonadotropins LH and FSH.

Option (4) Estrogen — Incorrect. Estrogens are secreted by the growing ovarian follicles.

NCERT Extract:
Gametogenesis – “… Spermatogenesis starts at the age of puberty due to significant increase in the secretion of gonadotropin releasing hormone (GnRH). This, if you recall, is a hypothalamic hormone. The increased levels of GnRH then acts at the anterior pituitary gland and stimulates secretion of two gonadotropins – luteinising hormone (LH) and follicle stimulating hormone (FSH).”