Effect of indomethacin on transcapillary exchange.

The effect of isosmotic hypervolaemia induced by intravenous saline infusion, on the Evans blue space, haematocrit, plasma protein concentration and urine output in dogs under anaesthesia was investigated. In hypervolemia, the Evans blue space increased by 25--30%, while the haematocrit did not change. The change in the plasma protein level was the same as that observed in control animals. Urine output increased significantly under the effect of hydration. When 4 mg/kg of indomethacin was given before a saline load, the Evans blue space did not change under the effect of hydration, the haematocrit decreased significantly, and the plasma protein level changed in the same way as in the two other groups. Urine output did not exceed the control value (without hydration) in spite of the saline load. It is concluded that indomethacin pretreatment inhibits the transcapillary fluid exchange.