NASAL SALT GLAND: INDEPENDENCE OF SALT AND WATER TRANSPORT.

The nasal salt-secreting gland of the domestic duck can produce a fluid with a sodium chloride concentration about three times that in blood plasma. To study the cellular mechanism responsible for the formation of the highly concentrated fluid, the gland was poisoned by retrograde injection of mercuric chloride into the lumen, decreasing the salt concentration to that in plasma while the volume of secretion was unchanged. Carbonic anhydrase inhibitor (acetazoleamide) caused a moderate decrease in salt concentrations, again with maintenance of volume of secretion. The results suggest that concentration and volume of the secreted fluid depend on two different cellular mechanisms.