Influence of Pituitrin on Diuresis Variously Induced.

Abstract

The diuretic action of extracts of the pituitary body was first described by Magnus and Schafer. 1 Their finding has been confirmed repeatedly. Von den Velden 2 showed that pituitrin may exert an opposite or antidiuretic effect. Reasoning that the polyuria of diabetes insipidus was caused by pituitary deficiency, he further used pituitary extracts successfully in the control of the polyuria. Recent papers by Smith and McClosky, 3 Fromherz, 4 and Stehle 5 give a review of the literature. As yet there is no general agreement as to the explanation of the apparently contradictory results.

The experiments reported in this paper were limited to a study of the action of pituitrin superimposed on a diuresis variously induced, and to a comparison of the effect of variation in dosage and method of administration. It was hoped that such experiments might throw some light on the question of the mechanisms responsible for the antagonistic actions reported. Rabbits anesthetized with morphine and urethane were used throughout the experiments. Cannulae were inserted in the ureters and urine flow recorded by a drop counter. Blood pressure from the carotid was recorded simultaneously. By means of a Woodyatt injecting pump, solutions warmed to body temperature were injected at a uniform rate. In this way diuresis was induced and the effect of pituitrin upon this existing diuresis was studied. When injection is continued in this way at a rate varying from 2.5 cc. per minute to .5 cc. per minute, depending on the solution employed, the diuresis usually begins gradually and mounts slowly to a plateau like level which often may be maintained for some hours, provided Mood pressure remains uniform. In a few instances among the controls, the slow rise continued until the end of the experiment. Such instances were associated with gradual rise of blood pressure.