THE ACTION OF PITUITARY EXTRACT ON URINARY SECRETION

¹ Department of Pharmacology, University of Edinburgh

1. In anæsthetised animals, intravenous administration of pituitary extract produces a definite diuresis.

Continuous intravenous administration of pituitary extract in 0·9 per cent. saline solution produces the same result.

2. In unanæsthetised dogs, pituitary extract administered subcutaneously controls the diuresis which normally would result from the administration of water or normal saline solution by the mouth. If concentrated saline solution is used, diuresis results.

A diuresis produced by drinking 230 c.c. of 5 per cent. urea solution was prolonged, but its onset was not delayed, by the subcutaneous administration of pituitary extract.

3. Delay in the absorption of fluid from the alimentary tract, if it occurs after pituitary extract administration, is insufficient to account for a delay in the onset of the diuresis for three and a half hours.

4. A subcutaneous injection of pituitary extract controls a diuresis produced by the intravenous administration of 120 c.c. of Ringer solution at the rate of 4 c.c. per minute ; if, however, the intravenous administration is given at the rate of 12 c.c. per minute, no antidiuretic effect occurs.

5. The hæmoglobin percentage in human beings is not appreciably altered by the drinking of large quantities of water. If, however, the drinking of large quantities of water is immediately preceded by a subcutaneous injection of pituitary extract, a definite reduction in the hæmoglobin percentage occurs during the first two hours of the experiment.