Question

GnRH secreted from hypothalamus mainly stimulates the release of?
a) Thyroxine from thyroid gland
b) ADH from posterior pituitary
c) FSH and LH from anterior pituitary
d) Aldosterone from adrenals

Answer 1

Hint: GnRH is gonadotropin releasing hormone. It is a hypothalamic hormone,which means released from hypothalamus , which stimulates the pituitary glands to synthesize and release the gonadotropins. Therefore, GnRH is a releasing hormone.

Complete answer:
Spermatogenesis starts at the age of puberty due to significant increase in the secretion of gonadotropin releasing hormones (GnRH) from hypothalamus. The increase in GnRH acts at the anterior pituitary gland which further acts on FSH and LH. This FSH acts on the Sertoli cells and stimulates secretion of some factors which helps in the process of spermiogenesis. LH however acts on Leydig cells and stimulates synthesis and secretion of androgen. Androgen in turn helps in the process of spermatogenesis.
So the answer is, option C, that is FSH and LH from anterior pituitary.

Additional Information:
The hypothalamus not only has nervous activity but also controls endocrine functions. The hypothalamus contains several groups of neurosecretory cells, which secrets hormones. These cells are called neuro secretory cells because these are in fact the hypothalamic neurons which produce the hormones. The hormones secreted by hypothalamic neurons or neurosecretory cells are called the hypothalamic hormones.

Note:
Diencephalon consists of thalamus, hypothalamus and epithalamus. Hypothalamus is as the name implies, hypothalamus Nestle at the base of the thalamus, and so of the brain. It is another very important part of the forebrain or brain.