Prostaglandin E2 enhances the sodium conductance of exocrine glands in isolated frog skin (Rana esculenta) |
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Authors: | Robert Nielsen |
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Affiliation: | (1) Institute of Biological Chemistry A, University of Copenhagen, DK 2100 Copenhangen, Denmark |
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Abstract: | Summary Prostaglandins are known to stimulate the active transepithelial Na+ uptake and the active secretion of Cl– from the glands of isolated frog skin. In the present work the effect of prostaglandin E2 (PGE2) on the glandular Na+ conductance was examined. In order to avoid interference from the Na+ uptake and the glandular Cl– secretion the experiments were carried out on skins where the Cl– secretion was inhibited (the skins were bathed in Cl– Ringer's solution in the presence of furosemide, or in NO3– Ringer's solution), and the active Na+ uptake was blocked by the addition of amiloride. Transepithelial current, water flow and ion fluxes were measured. A negative current was passed across the skins (the skins were clamped at –100 mV, basolateral solution was taken as reference). When PGE2, was added to the skins under these experimental conditions, the current became more negative; this was mainly due to an increase in the Na+ efflux. Together with the increase in Na+ efflux a significant increase of the water secretion was observed. The water secretion was coupled to the efflux of Na+, and when one Na+ was pulled from the basolateral to the apical solution via this pathway 230 molecules of water follwed. From the data presented it is suggested that this pathway for Na+ is confined to the exocrine glands. |
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Keywords: | Electro-osmosis frog skin glands local osmosis prostaglandin E2 sodium conductance |
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