This substance is prepared from the suprarenal glands of sheep, and is used in the form of a watery extract or as an active principle under the name of adrenalin or suprarenalin.
It has no action on the skin, but it blanches mucous membranes by causing contraction of the blood vessels. If the solution is injected hypodermatically, intravenously, or if it is absorbed from mucous membranes other than that of the gastrointestinal canal it stimulates the heart, contracts the arterioles, raises the blood-pressure, and tones up the muscular system. The increase in blood pressure is, however, of short duration. Large doses depress the respiratory center.