Ammonia excretion by the gills of two marine teleost fish: The importance of NH4+ permeance
✍ Scribed by Goldstein, Leon ;Claiborne, James B. ;Evans, David E.
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 259 KB
- Volume
- 219
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Varying the concentration of un-ionized ammonia (NH,) in the medium perfusing the gills of the isolated fish head while holding the total ammonia (NH,' + NH,) concentration constant had no significant effect on gill ammonia excretion. In contrast, alteration in the medium NH,+ concentration at a fixed NH, concentration produced a significant change in ammonia excretion. Thus, gill ammonia excretion was concentration.
Ammonia is either the chief or a major nitrogenous end-product excreted by aquatic, gilled organisms (Forster and Goldstein, '69; Kormanik and Cameron, '81). This potentially toxic product is rapidly eliminated by the gills of these organisms. In an aqueous solution ammonia exists as a mixture of the ionized and unionized forms: NH,+ + NH, + H'. Although