Isolation of Enteramine from Extracts of Posterior Salivary Glands of Octopus Vulgaris and of Discoglossus Pictus Skin

The present paper describes the main characteristics of natural enteramine as well as a procedure for its isolation. In another paper the preparation and the characteristics of synthetic enteramine have been considered (1). Vertebrates and some groups of invertebrates possess a particular system of cells, known as the enterochromafin cell system, which contains specific granules characterized by several well defined and distinctive chemical and physicochemical features (chromaffinity, argentaffinity, fluorescence in Wood's light, ability to couple with diazonium salts, and fixation by formolcontaining histological fixatives). The cells of this system may be distributed within the gastrointestinal mucosa (2-4) or skin (or both) (5) or else massed in well defined glandular formations (6-9). The specific secretion or storage product of the enterochromaffin system has been termed enteramine (10, 11). A number of color tests and biological reactions suitable for the detection and quantitative determination of this substance have been described (12-14). The pharmacological effects exerted by enteramine are (a) a powerful stimulating action on the estrous uterus and the duodenum of the rat, the small intestine of the rabbit, the urinary bladder of the dog, both isolated and in situ, and the heart of mollusks (15) ; (b) a moderate action on the systemic blood pressure, which may be hypotensive, hypertensive, or biphasic, according to the animal species, the dose, and the state of the circulatory system (16) ; (c) an intense antidiuretic action, especially evident in hydrated rats. Diuresis may be reduced in these animals even after a subcutaneous injection of as little as 5 y of enteramine per kilo of body weight. This dose is at least 50 to 100 times smaller than that needed to affect the systemic blood pressure and at least 10,000 times smaller than the median lethal dose by the subcutaneous route. Furthermore, enteramine acts selectively on the contractile structures of the afferent vascular bed of the glomerulus, causing an increase in tonus, or spasm (17). With high single doses or with repeated doses, the vascular spasm leads to a severe and lasting ischemia, resulting in more or less extensive degeneration and necrosis of large sections of the cortex of the kidney.'