Relationship between the concentration of corticosteroids in avian plasma and nasal gland function.

Abstract

SUMMARY Nasal gland salt secretion and plasma corticosteroid concentrations in wing venous plasma were measured at 15 min. intervals after intravenous loading of male ducks (Anas platyrhynchos) with 154 mm- or 500 mm-NaCl and gulls (Larus argentatus) of undetermined sex with 500 mm-NaCl. Plasma corticosteroids were measured by fluorimetry, Na+ and K+ in nasal fluid by flame photometry, and changes in plasma volume of the duck by dye dilution. Age and/or seasonal variations in plasma corticosteroid concentrations were observed in the duck. Corticotrophin (10 i.u./kg. in the duck and 20 i.u./kg. in the gull) caused a progressive rise in plasma corticosteroid concentrations in both species. The nasal glands began to secrete in both species within 15 min. after loading with 500 mm-NaCl but in the gull the secretion rate reached a peak earlier and declined more rapidly. Although no clear relationship between adrenocortical and nasal gland functions was found in either species, comparison of changes in plasma corticosteroid concentrations and plasma volume in the duck under both conditions of saline loading supported this connexion.