Subcommissural organ and water metabolism

¹ Department of Anatomy, University of Vermont College of Medicine, Burlington, Vermont

The subcommissural organ (SCO) of white rats was destroyed by the use of discrete (1–1.5 mm) lesions. Water intake, urine output, and urine Na and K were measured, and the kidneys examined for changes in the granular cell index. Water intake following complete SCO destruction was reduced for 1 day and then returned to preoperative levels. This change was no different from that observed in rats with no destruction or only partial destruction of the SCO. Urine output fell following SCO destruction and slowly returned toward normal. Rats with partial or no destruction of the SCO showed no change in urine output. All the rats showed a postoperative drop in urine Na and K. There was no change in the granular cell index. Our evidence indicates that the SCO plays no role in water metabolism through control of thirst or through control of aldosterone secretion.