1. In rats with inherited diabetes insipidus, unilateral nephrectomy plus drinking of 0·6% NaCl solution (saline) did not influence blood pressure in adult rats. However, when these factors applied before puberty, they produced hypertension.
2. We therefore analysed whether saline administration before puberty or unilateral nephrectomy before puberty was more important for this hypertensive response.
3. Saline drinking was found to be necessary for the response because hypertension was elicited by unilateral nephrectomy in adult rats only if saline consumption began before puberty.