THE RENAL EXCRETION OF AN ANTIDIURETIC SUBSTANCE BY THE DOG

Abstract

A diabetes insipidus dog is a good test animal for determining the antidiuretic activity of urine. The urine in the fresh untreated state is injected intraven. in quantities up to 100 cc. An increase in the conc. of the urine of the test animal, as measured by the creatinine U/P ratio, is a positive response. Tested in this manner, the urine of normal dogs deprived of drinking water 2-4 days contains an antidiuretic material. The urine of diabetes insipidus dogs, similarly treated, contains none. The absence of antidiuretic material from the urine of the diabetes insipidus dog is not due to the inability of the kidney to excrete the substance but is associated with an enormously reduced antidiuretic content of the post. lobe of the pituitary.