(n): the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect
(n): any of a group of chemicals including epinephrine and norepinephrine that are produced in the medulla of the adrenal gland
(n): a neurochemical that transmits nerve impulses across a synapse
(n): any agent that causes a narrowing of an opening of a blood vessel: cold or stress or nicotine or epinephrine or norepinephrine or angiotensin or vasopressin or certain drugs; maintains or increases blood pressure
