I.—The action of pituitary extracts upon the kidney

Abstract

It was noticed in 1901 by P. Magnus and Schäfer that intravenous injection of pituitary extract may be followed by a marked increase in urine flow, accompanied by expansion of the kidney. This appeared the more remarkable, since the effect of the extract is to cause contraction of the systemic arteries, including those of the alimentary canal, a contraction only inferior to that produced by the active material of suprarenal extract; and it was to have been anticipated that the same effect would be produced upon the kidney vessels, leading to a diminution or suppression of urine. As will appear from the sequel, this effect does, in fact, sometimes occur as a primary result of the injection of pituitary extract, but even when this is the case it is, in the majority of instances, succeeded by prolonged dilatation of kidney vessels accompanied by marked diuresis. It has been our aim in the present investigation to follow up the line of research indicated by the observations of Magnus and Schäfer, and to endeavour definitely to determine how far this diuretic action is constant, with which part of the pituitary body it is related, whether it is a function of the substance which raises the blood-pressure and is only an indirect effect of this rise, or whether it is due to a substance which exerts a specific effect upon the renal blood-vessels and kidney cells, and in the latter case whether it is possible to isolate this material and exhibit its action independently.