The effect of pituitrin on blood and on lymph and urine production.

The diuretic action of pituitary extract described first by Magnus and Schäfer 1 has since been observed by many. More recently an anti-diuretic action of this extract has been observed, especially in connection with diabetes insipidus, and in relation to water intoxication. (For literature see Weir, Larson and Rowntree. 2 ) On account of its diuretic action one might expect some effect on the composition of the blood. Underhill and Pack 3 and Mackersie 4 observed a dilution of the blood after pituitrin injection, but only a few experiments were made. Rowntree, 2 however, observed no change in blood volume, and Lamson, 5 who injected physiological salt along with pituitrin observed no change with small doses, but found that after large doses of pituitrin, the physiological salt did not leave the blood as it normally does, but kept the blood diluted for hours.

We have followed the concentration of the blood in 20 dogs after pituitrin injection, using 2 or 3 cc. of Parke Davis's obstetrical pituitrin. In 16 of these cases the effect was so very slight as to be within the limit of error. Most of the slight effects observed tended to be more toward dilution than towards concentration. In one case there was a marked dilution of the blood; the hemoglobin falling to 74.1 about an hour after injection, corresponding to the effect observed by Underhill corresponding to the effect observed by Underhill. In three cases there was a marked increase in the concentration of the blood, the hernoglobin rising to 111, 108 and 107, respectively. A concentration of the blood is what one might expect'from a rise of blood pressure. We have also confirmed Lamson's observations that physiological salt is delayed in its exit from the vessels.

The flow of lymph from the thoracic duct has ken followed in 11 cases, and in 9 of these the urine flo'w was also studied. In every case the injection of pituitrin caused a marked slowing of the lymph flow which lasted some time. One example may be given from a dog anaesthetized with morphia and ether: normal from the thoracic duct, 3 drops per minute; injection of physiological saline (300 cc.) caused an increase to 13 drops per minute; injection of 2 cc. pituitrin caused a drop to 6 cc. per minute which remained at that level for one hour, when a further injection of physiological saline (200 cc.) caused an increase to 23 drops per minute.