Epinephrine

Epinephrine is a hormone known as adrenaline. It is a catecholamine, a sympathomimetic monoamine derived from the amino acids phenylalanine and tyrosine. Epinephrine is the fight or flight hormone which is released from the adrenal glands. It increases heart rate, dilates the pupils, and constricts arterioles in the skin and gut while dilating arterioles in muscles. Epinephrine elevates blood sugar levels by increasing catalysis of glycogen to glucose and at the same time begins the breakdown of lipids in fat cells. Like other stress hormones, epinephrine has a suppressive effect on the immune system.