The hormones vasopressin(ADH) and oxytocin (OT) are released by _____.
Posterior lobe of pituitary
The posterior lobe of pituitary releases the following two peptide hormones. Both these hormones are synthesized in the hypothalamus and are carried to the posterior pituitary along with nerve fibers where they are stored. From posterior pituitary, they are released into the blood.
1. Vasopressin or Antidiuretic hormone (ADH) - It is released from posterior pituitary in response to stress and dehydration. It increases the reabsorption of water in the distal convoluted tubules and the collecting tubules of kidney. So its deficiency in the body increases the urine flow causing diabetes insipidus. It also raises blood pressure by constricting the peripheral blood vessels.
2. Oxytocin is an important uterus-contracting hormone at the time of childbirth. It also acts on mammary glands and helps in the expulsion of milk at the time of suckling. It is, therefore, also known as `milk-ejection hormone’ and `birth hormone’. It decreases the blood pressure by dilating the peripheral blood vessels (opposite to that of vasopressin).