STUDIES ON DIABETES INSIPIDUS

Abstract

A substance having diuretic properties has been extracted from sections of the brains of dogs, cut in such a way as to include as nearly as possible only the mammillary bodies. The substance is present in much larger quantities in dogs suffering from experimental diabetes insipidus than in normal dogs. It has not been found in extracts of other regions of the brain. It is not precipitated by phosphotungstic acid. A substance having diuretic properties has also been demonstrated in blood of dogs suffering from experimental diabetes insipidus but not in blood of normal dogs. It is less active after the preparation has been charred, is destroyed by prolonged boiling in a weakly alkaline solution, is relatively stable in neutral solutions and in dry form, and is not precipitated by phos- photungstic acid. The substances in the mammillary region and in the blood both cause the same type of diuresis, an excessive response to diuretics injected during the period in which they are acting, and produce manifestations of thirst. Efforts to detect a similar diuretic substance in urine failed.