The effect on drinking in the rat of intravenous infusion of angiotensin, given alone or in combination with other stimuli of thirst.

1. Intravenous infusion of angiotensin causes rats which are in water balance to drink water.2. The mean amount of angiotensin needed to initiate drinking was 29.1 +/- 4.6 mug/kg (S.E. of mean) in twenty normal rats, and 15.7 +/- 2.1 mug/kg in thirty-four nephrectomized rats.3. The nephrectomized rat is therefore more sensitive to this action of angiotensin than the rat with intact kidneys.4. The rates of infusion (0.05-3.0 mug/kg(-1) min(-1)) which cause drinking are comparable to those used to produce other effects in rats.5. Angiotensin restores the drinking response of the nephrectomized rat subjected to caval ligation to a value similar to that obtained in the uninfused normal rat subjected to caval ligation.6. The effects of angiotensin and hypertonic saline on drinking are additive when both substances are administered to nephrectomized rats.7. These experiments provide further support for the view that the renin-angiotensin system is concerned in extracellular thirst.