Increase of hematocrit in experimental renal hypertension and its reversal.

Hematocrit can be increased in experimental animals with renal hypertension of two-kidney type. The present study showed that the increased hematocrit was returned to normal by removal of the clipped kidney. The left renal artery was clipped in 13 rabbits with an intact contralateral kidney, and a sham operation was performed in 10 rabbits as a control. After an interval of 10 weeks the left kidney was removed in all animals. Blood pressure, hematocrit, hemoglobin content, and erythrocyte count were rapidly increased and remained raised after clipping of the renal artery but they did not show any significant changes after sham operation. A transient but significant increase of reticulocyte count was found at the end of the first week after clipping of the renal artery. Removal of the clipped kidney was followed by a rapid return of hematocrit, hemoglobin content, and erythrocyte count to normal within 2 weeks. Blood pressure was also decreased but not returned to normal by removal of the clipped kidney.