1. The tonin concentration of saliva and submaxillary glands was studied in one-clip hypertensive rats with or without the contralateral kidney.
2. Salivary tonin concentration was elevated in one-kidney hypertensive rats, but not in one-kidney normotensive or two-kidney, one-clip hypertensive rats. In contrast, an elevated submaxillary gland tonin concentration was found only in uninephrectomized animals, whether normotensive or hypertensive.
3. A single intravenous administration of rabbit tonin antiserum into one-kidney hypertensive rats restored blood pressure to normal in seven out of ten animals. There was little change in blood pressure in two-kidney, one-clip hypertensive, uninephrectomized or sham-operated rats.
4. These findings suggest a connection between the physiology of the kidney and of the submaxillary gland in the rat, and indicate that tonin may play a significant role in maintaining high blood pressure in one-kidney hypertensive animals.