A Pharmacologically Active Substance in Serum and Platelets Which Stimulates the Suprarenal Medulla

Abstract

In a previous communication (Reid, 1946) it was shown that the well-known muscle-stimulating activity of serum or platelet extracts is not due to histamine. In the course of that investig-ation it was necessary to compare the effeot of various preparations with that of histamine on a number of different kinds of test object. It is known that histamine liberates adrenaline from the suprarenal gland and this property has been used as a confirmatory test for the assay of histamine in tissue extracts (Peldberg and O'Connor, 19137). I found, when I injected cat serum (whieh on other gi'onnds had been shown to contain little or no histamine) intra-arterially into the suprarenal glands of the cat that it, also, caused what appeared to be an output of adrenaline; and so for the time being, I laid that observation aside and made no more experiments with that particular type of preparation.This paper reports experiments on the aetion of serum and extracts of blood on the suprarenal gland. METHODS.Experiments ivere made on thirty-eight eata, with two confirmatory experiments on dogs. After preliminary ether anaesthesia the animals were given an intravenous injection of chloralose or, in the case of one eat, tieeapitated. The vagua ncrvea were divided, and usually the animal was artificially ventilated. Tiitra-arterial injections into the suprarenal giand were made by tlie method of Feldberg and Minz (1!)31). Essentially, this couaiafa of evisceration, tying the renal arteries and the aorta below their origin and inserting a metal eannula into the cnt stump of either the eoeliac or siiperior mesenterie artery. Injections up to l-O ml. volume were made through this cannula; intravenous injections were given through the external jugular vein. Sometimes the splanchnic nerves were divided and in some experiments injections were repeated after excision of the suprarenal glands. The blood pressure was recorded from the left common carotid artery by means of a mercury manometer, the cannula being filled with saturated sodium sulphate solution, and sometimes, in addition, the response of the right nictitating membrane of a cat whose right superior cervical ganglion had been removed Bome two weeks before the final experiment, was recorded with a 6:1 magnification. In 1 Technical assistance waB provided by a grant from the National Health and Medical Besearch Council.