Which hormone is released by the posterior pituitary gland?

The hormone released by the posterior pituitary gland is antidiuretic hormone (ADH). This hormone plays a crucial role in regulating water balance in the body. It acts primarily on the kidneys, promoting the reabsorption of water back into the bloodstream, which helps to concentrate urine and maintain hydration levels.

ADH is produced in the hypothalamus and transported to the posterior pituitary gland, from where it is released into the bloodstream in response to changes in the body's hydration state or blood osmolality. This release mechanism highlights the critical interaction between the hypothalamus and the pituitary gland in maintaining homeostasis.

In contrast, hormones like growth hormone and cortisol are produced by different glands; growth hormone is secreted by the anterior pituitary and cortisol is produced by the adrenal cortex. Adrenaline, also known as epinephrine, is secreted by the adrenal medulla. Each hormone has distinct functions and is released by different parts of the endocrine system, underscoring the specificity of hormonal actions based on their source and target tissues.