THE EXCRETION OF POSTERIOR PITUITARY ANTIDIURETIC HORMONE IN THE URINE AND ITS DETECTION IN THE BLOOD1

Abstract

By the use of pressure-dialysis through cellulose tubing it was possible to separate the urinary antidiuretic hormone of the posterior pituitary of dogs into a large fraction with a high mol. wt. and a smaller fraction with a low mol. wt. This latter fraction could not be concentrated in the ultracentrifuge, but since the clear soln. becomes turbid on addition of trichloroacetic acid, it is thought to be a protein. It is possible, but unlikely, that this active fragment is absorbed into a large inactive fragment. Antidiuretic hormone was secreted by the posterior pituitary of dogs in response to stimulation of the cerebral asmoreceptors by dehydration and could be detected in the internal jugular blood in concn. of 50 M. V./100 cc.