Role of Hormones in Initiating Reproductive Function

Pituitary gland – growth hormone - Needed for normal growth of a person, controls secretion of other glands.

Thyroid glandthyroxine - Needed for metabolism. Its deficiency causes goiter. In frogs, it controls metamorphosis (In insects also, hormones control metamorphosis).

Pancreas – insulin - Needed for sugar breakdown. Deficiency causes diabetes.

Adrenal glandsadrenaline - Needed for adjustment to stress, maintain the salt balance of the body.

Ovaries estrogen - (secondary sexual features in females, egg production).

Testestestosterone - (secondary sexual features in males, sperm production).

What are Hormones?


The chemical substances secreted by endocrine glands are known as hormones. They control the changes occurring in adolescence. The onset of puberty is controlled by sex hormones.

Role of Hormones during Adolescence:-

The pituitary gland releases hormones to stimulate testes in males and ovaries in females.

Testosterone and Estrogen (Produced by testes and ovaries respectively) are released into the bloodstream which reaches the target site and produces puberty changes.

  • There are endocrine glands present in humans with secrete chemical substances in the body is called the Hormones. These chemical substances are responsible for changes in the human body at the time of puberty.
  • The hormones act as messengers and are responsible for transporting signals from one cell to another.  Hence they evoke responses from various organs of the body and tissues. Hormones have certain properties or characteristics such as:
  • They are secreted by the endocrine glands.
  • They circulate in the body fluids.
  • They are responsible for regulating the behavior of the target cells.
  • They cause long-term effects in the body like change in behavior, change in growth, development of organs, puberty menopause, etc.
  • Hormones are secreted in limited quantities from time to time whenever they are required by the body.
  • Different glands present in the body are responsible for the secretion of different hormones.
  • The nervous system regulates the flow of hormones in the body. 
  • The endocrine glands are also called Ductless Glands because they secrete the hormones directly into the blood. In males, the testes secrete the male hormones or testosterone. In females, the ovaries secrete the female hormones or Estrogen.


What are Pituitary glands?

  • There are pituitary glands present in the body switch control the production of the hormones by endocrine glands in both males as well as females.
  • The part of the body for which a particular hormone is meant is called the Target Site.
  • The endocrine glands secrete the hormones in the blood and it reaches the target site. Then the target site response accordingly.
 Hormones initiate Puberty