Active sulfate secretion by the intestine of winter flounder is through exchange for luminal chloride

Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269; and Mount Desert Island Biological Laboratory, Salisbury Cove, Maine 04672 SO transport by winter flounder intestine in Ussing chambers was characterized. With 50 mM SO (physiological level) bathing the...

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Bibliographic Details
Published in:American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2003-02, Vol.284 (2), p.380-R388
Main Authors: Pelis, Ryan M, Renfro, J. Larry
Format: Article
Language:English
Subjects:
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid - pharmacology
Absorption - drug effects
Animals
Biological Transport, Active - drug effects
Chlorides - metabolism
Electric Conductivity
Fishes - metabolism
Food
Glucose - metabolism
Intestines - drug effects
Intestines - metabolism
Microvilli - drug effects
Microvilli - metabolism
Ouabain - pharmacology
Potassium - pharmacology
Sodium Cyanide - pharmacology
Sulfates - metabolism
Time Factors
Valinomycin - pharmacology
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Summary:Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269; and Mount Desert Island Biological Laboratory, Salisbury Cove, Maine 04672 SO transport by winter flounder intestine in Ussing chambers was characterized. With 50 mM SO (physiological level) bathing the lumen, net absorption (lumen to blood) dominated. Under short-circuited conditions, 1 mM SO on both sides, net active SO secretion occurred (8.55 ± 0.96 nmol · cm 2 · h 1 ). NaCN (10 mM), ouabain (10 4 M), and luminal DIDS (0.2 mM) inhibited net secretion. Removal of luminal Cl and HCO together (Cl -HCO ) or Cl alone blocked net secretion, whereas removal of luminal HCO alone increased net secretion. SO uptake into foregut brush-border membrane vesicles was stimulated by a trans-Cl gradient (in > out) and unaffected by a trans-HCO gradient (in > out). Short-circuiting with K + (in = out) and valinomycin had no effect on Cl -stimulated SO uptake, suggesting electroneutral exchange. Satiety (i.e., full stomach) stimulated the unidirectional absorptive flux, eliminating net secretion. It was concluded that the intestine is a site of SO absorption in marine teleosts and that active SO secretion is in exchange for luminal Cl . Pleuronectes americanus ; anion exchange; osmoregulation
ISSN:0363-6119
1522-1490
DOI:10.1152/ajpregu.00573.2002