Studies of the Relation of the Pituitary to Watermetabolism.

Abstract

Recent studies of Hoff and Wermer 1 reveal the presence of increased quantities of pituitary hormone in the cerebrospinal fluid after administration of diuretics. They explain their observation of increased liberation of antidiuretic substances from the posterior pituitary lobe, as an attempt on the part of the body to prevent excessive loss of water. In other words, it is a compensatory process.

The following studies were made to reveal whether there are demonstrable changes in the hypophysis after the administration of diuretics and whether such changes precede or follow the loss of water.

The experiments were made on guinea pigs of the same breed and weighing from about 250 to 600 gm. Only male animals were used. We used novasurol in a dilution of 1 to 25 of the commercial preparation. One cc. was given subcutaneously to each animal. We kept the guinea pigs without food after the injection. They were killed at intervals of 20 minutes, 40 minutes and 1, 2, 3, and 6 hours. Their hypophysis was removed, fixed in Zenker's solution and studied histologically.

We determined the loss of water by weighing the animals before and after administration of the diuretics. Weighing was chosen as our method in order to account also for loss of water by ways other than diuresis.

Normal guinea pigs kept without food lose 3.5% of their body weight as an average within 6 hours. In contradistinction to this, the animals which were given novasurol lost 5.2% of their weight within the experimental period of 6 hours. These figures tallied well with those obtained on a series of white mice. The average loss of weight in normal mice kept without food for 6 hours was 3.6% whereas mice after the administration of novasurol lost 4.8% weight in the same time.