THE DIURETIC ACTION OF PITUITARY EXTRACTS AND THE RESPONSIBLE PRINCIPLE OR CONSTITUENT

¹ Department of Pharmacology, McGill University, Montreal, Canada

1. A method is described for accurately observing small changes in the rate of urine secretion in the anesthetized rabbit.

2. Using this procedure, it is shown that the two pressor preparations from the pituitary gland, pitressin and postlobin-V, show approximately equal diuretic effects in the urethanized rabbit. The two oxytocic preparations, pitocin and postlobin-O, also exert equal effects, but higher dosages (twentyfold) are required. Finally, comparisons of all four preparations on the basis of pressor content suggest that the diuretic effects observed are due to pressor material present in each preparation (contaminating pressor substance in the case of the oxytocic preparations). The oxytocic constituent probably exerts no diuretic action.