Early response of the hamster kidney to cold exposure and unilateral nephrectomy

Abstract

1. 1. Renal enlargement and DNA synthesis were studied in adult male hamsters at 1–5 days and at 2 weeks following either unilateral nephrectomy or cold exposure (4°C) alone or in combination. 2. 2. Either treatment alone caused a 40–45 per cent increase in renal wet weight within 2 weeks. When the treatments were combined the effects were additive. 3. 3. Per cent dry weights were decreased only in cold-exposed hamsters after 2 weeks of treatment. 4. 4. Renal cortical DNA synthesis, as determined by the use of radioautography after the injection of tritiated thymidine, was increased significantly at 2 days after unilateral nephrectomy, at 14 days after cold exposure and at 5 and 14 days when animals received the combined treatment. 5. 5. DNA synthesis in the outer medulla was increased significantly at 2 weeks after cold exposure and at 3, 5 and 15 days after both unilateral nephrectomy and exposure to the cold. 6. 6. Within the inner medulla only the combined treatment for 14 days caused a significant increase in DNA synthesis in tubular epithelia.