Salt gland secretion produced by the gull, Larus glaucescens in response to stomach loads of different sodium and potassium concentration

Abstract

1. 1. The sodium, potassium, chloride and osmotic concentration of salt gland secretion produced by glaucous-winged gulls, Larus glaucescens, given osmotically equal stomach loads: 400 Na, 100 K; 250 Na, 250 K; 100 Na, 400 K; or 500 K (chloride) m-equiv/l. were determined. 2. 2. In the first hour the 400 Na, 100 K m-equiv/l. loads resulted in the rapid production of a large volume (14 ml) of secretion, high in sodium (646 m-equiv/l.) but not high in potassium (61 m-equiv/l.) with a Na-K ratio of 12:1. The 100 Na, 400 K m-equiv/l load resulted in slow production of little secretion (1 ml) lower in sodium (510 m-equiv/l.) but higher in potassium (135 m-equiv/l.) with a Na-K ratio of 4:1. 3. 3. KCl alone (500 m-equiv/l.) did not initiate any salt gland secretion. 4. 4. KCl was not effective as a stimulant for salt gland secretion when given in the same concentration as NaCl in stomach loads and may, in fact, decrease the effectiveness of NaCl stimulation possibly by decreasing the uptake of sodium from the intestinal tract.