Assertion : LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. 

Reason : Spermatogenesis is initiated during the embryonic development due to significant increase in the secretion of gonadotropin releasing hormone (GnRH).

Assertion is true and Reason is false.

The correct answer is Option (3): Assertion is true and Reason is false.

Each seminiferous tubule is lined on its inside by two types of cells called male germ cells (spermatogonia) and Sertoli cells. The male germ cells undergo meiotic divisions finally leading to sperm formation, while Sertoli cells provide nutrition to the germ cells. The regions outside the seminiferous tubules called interstitial spaces, contain small blood vessels and interstitial cells or Leydig cells.

Leydig cells synthesise and secrete testicular hormones called androgens. Other immunologically competent cells are also present.

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).

LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. Androgens, in turn, stimulate the process of spermatogenesis.