THE EFFECT OF PROLONGED INTRAGASTRIC INFUSIONS OF ISOTONIC AND HYPERTONIC SALINE ON WATER AND SODIUM EXCRETION AND ON EXCHANGEABLE BODY SODIUM IN NORMAL AND ADRENALECTOMIZED RATS

¹ Department of Pharmacology and Therapeutics, University of Sheffield

A method is described for implanting stomach tubes into rats. This has been used to study the effects on sodium metabolism of prolonged infusions of saline in normal and adrenalectomized rats. Adrenalectomy resulted in a delay in the excretion of sodium and water, but the excess fluid was excreted within 12 hr. of stopping the infusion. This fluid retention was associated with a considerable reduction in voluntary fluid intake. Adrenalectomized rats infused for 4 days with either 55 ml. of 2 per cent saline or 95 ml. of 0·9 per cent saline daily showed no increase of total exchangeable sodium when this was measured 12 hr. after stopping the infusion.

In normal rats infused with 2 per cent saline, GFR rose immediately and remained elevated throughout the infusion. When 0·9 per cent saline was given, a rise did not occur until the 5th hr. of infusion. The adrenalectomized rats showed no significant changes in GFR with either solution. The delay in dosium excretion after adrenalectomy appears to be due, in part, to an alteration in renal tubular function.

Note:

My thanks are due to Professor G. M. Wilson for his generous advice and encouragement.