Effect of Pituitary Extract (Posterior Lobe) on the Concentrations and Distributions of Chlorides and Bromides in the Blood and Urine.

Abstract

The mechanism by which pituitary extract causes antidiuresis in unanesthetized mammals has been considered By some workers as chiefly extra-renal, by others as chiefly renal. The experiments reported here were undertaken in the belief that studies of electrolyte distribution (chlorides and bromides) between erythrocytes and serum might support or oppose the hypothesis that an extra-renal mechanism is involved.

All experiments were performed on unanesthetized dogs with permanent fistulae of only the ureteral portion of the urinary bladder for the accurate collection of urine. Blood was withdrawn from the jugular vein under oil, defibrinated and then centrifuged to separate the serum from the erythrocytes. The serum and the erythrocytes were transferred to separate tonometers without exposure to air. Determinations of the hydrogen-ion concentration of serum and of the water-content and concentrations of chlorides or of chlorides and bromides in urine, erythrocytes and serum, were made 3 or 4 times (including a control-period) in each experiment. Posterior-lobe pituitary extract was given subcutaneously (except in control experiments) in an amount sufficient to cause a typical antidiuretic effect.

The results obtained under the experimental conditions described above appear to justify the following conclusions: 1. Pituitary extract does not significantly change the concentrations of chloride in erythrocytes or in serum of intact (13 experiments on 5 dogs) or of nephrectomized dogs (2 dogs). 2. When part of the blood-chloride has been replaced by bromide, pituitary extract causes no change in the concentrations of chloride and of bromide or in the distributions of chloride or of bromide between erythrocytes and serum of intact (14 experiments on 6 dogs) or of nephrectomized dogs (5 dogs). The relative concentrations of bromides and chlorides are about the same in serum and urine (14 experiments on 6 dogs). 3. Pituitary extract causes no change in the water-content of erythrocytes or of serum (34 experiments).