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1. The composition of the nasal salt-glands of geese was found to be Na 57 ± 3·5 (S.E.), K 52·3 ± 3·9 and Cl 78·3 ± 11·0 m-equiv/kg fresh tissue. During secretion, the Na content was significantly raised to 72·4 ± 3·4 m-equiv/kg.
2. Salt-gland slices incubated in KrebsHenseleit bicarbonate medium plus glucose (6 mM), in the presence of [14C]sucrose as an extracellular marker had the following composition, Na 85·3 ± 3·1, K 37·1 ± 3·1 and Cl 74·3 ± 3·6 m-equiv/kg. The calculated intracellular concentrations were for Na 61·5 ± 2·1, K 105·3 ± 8·7 and Cl 37·8 ± 5·0 m-equiv/l. intracellular water.
3. Ouabain (10-4 M) significantly decreased the tissue and cell K concentration and significantly increased the Na concentration.
4. Acetylcholine (10-6 M) and eserine (10-4 M) in the incubation medium had no effect on intracellular composition.
5. Raising the Na concentration of the medium to 172 m-equiv/l. and the Cl to 156 m-equiv/l. in two experiments had no effect on the calculated intracellular composition.
6. These results do not support reports that the cells have a very high Na concentration (about 350 m-equiv/l. intracellular water). They are compatible with the hypothesis that the hypertonic secretion is formed across the luminal membrane of the secretory cell by an active Na+ pump and there are no data to suggest that Na+ is concentrated across the basal membrane by a ouabain-insensitive process.
7. The data are discussed in relation to permeability studies and to electrical potential measurements within the gland by other workers.
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