THE ANTI-DIURETIC ACTION OF PITUITARY

¹ Department of Pharmacology, University of Edinburgh

1. a. In the unanaesthetised animal subcutaneous injections of pituitary inhibit the diuresis from the administration of water by the mouth for four or five hours.

b. During this anti-diuretic period there is a rise in the amount of sodium chloride in the urine.

c. This anti-diuretic action can be overcome by the oral administration either of a 1.5 per cent solution of sodium chloride or a 5 per cent urea solution.

d. The anti-diuretic action of pituitary is not influenced by the division of the splanchnic nerves.

e. Where no water has been given pituitary produces a short phase of diuresis followed by a period of lessened secretion.

2. a. In the anaesthetised animal the administration of pituitary produces a short period of diuresis. The diuresis is associated with an acceleration of the renal blood flow. The short period of suppression preceding the diuresis is probably due to contraction of the smooth muscle of the ureters and bladder.

b. Under anaesthesia a water diuresis cannot be produced from the oral administration of water. The diuresis obtained from the intravenous administration of saline or sodium sulphate is not inhibited by pituitary.