Posterior pituitary hormones, vasopressin and oxytocin
Hormones are molecules synthesized and secreted into the blood circulation by specialized organs called endocrine glands. Hormones, carried by blood, act on one or more target tissues which contain specific receptors able to interact with hormones to produce specific effects.
Hormones have different chemical structures:- polypeptides for pituitary hormones, insulin, calcitonin, -steroids for sex hormones, corticosteroids, mineralocorticoids, - amino acid derivatives for thyroid hormones.
The two principal hormones secreted by the hypothalamus and stored in the posterior lobe of the pituitary gland are antidiuretic hormone, ADH also called vasopressin, and oxytocin.