Effects of pregnancy on glucose handling by rat kidneys.

1. Glomerular filtration rate (g.f.r.), and renal reabsorption and excretion of glucose, sodium and potassium were measured in 7-8 day pregnant rats and age-matched (12-13 week old) virgin controls undergoing saline and glucose infusions. 2. Pregnancy was associated with an increased g.f.r. and a decreased urine flow rate during both infusions. 3. During saline infusion, more glucose was excreted in pregnant animals than in virgins but with no significant difference in fractional reabsorption. During glucose infusion, pregnant animals excreted less glucose than virgins, owing to a decrease in the filtered load but with no significant difference in fractional reabsorption. 4. During both saline and glucose infusion, pregnant animals excreted less sodium than virgin controls. 5. During saline infusion, pregnant animals excreted more potassium. During glucose infusion, pregnant animals excreted less potassium than control animals.