Ion transport across the isolated intestinal mucosa of the winter flounder,Pseudopleuronectes americanus: II. Effects of cyclic AMP

1980 ◽  
Vol 55 (3) ◽  
pp. 157-163 ◽  
Author(s):  
Michael Field ◽  
Philip L. Smith ◽  
Jennifer E. Bolton
Keyword(s):  
Cyclic Amp ◽  
Ion Transport ◽  
Intestinal Mucosa ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus

Ion transport across the isolated intestinal mucosa of the winter flounder,Pseudopleuronectes americanus

1978 ◽  
Vol 41 (3) ◽  
pp. 265-293 ◽  
Author(s):  
Michael Field ◽  
Karl J. Karnaky ◽  
Philip L. Smith ◽  
Jennifer E. Bolton ◽  
William B. Kinter
Keyword(s):  
Ion Transport ◽  
Intestinal Mucosa ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus

Tyrosine transport in winter flounder intestine: interaction with Na+-K+-2Cl- cotransport

1987 ◽  
Vol 253 (2) ◽  
pp. R264-R269 ◽  
Author(s):  
M. W. Musch ◽  
F. M. McConnell ◽  
L. Goldstein ◽  
M. Field
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Intestinal Epithelium ◽  
Brush Border ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Ussing Chambers ◽  
Cellular Concentration ◽  
Coupled Process ◽  
Main Change

Tyrosine absorption across the brush border of the intestinal epithelium of the winter flounder Pseudopleuronectes americanus was studied in Ussing chambers modified to determine early rates of uptake. At 0.1 mM tyrosine, the 4-min rate of uptake (influx) of tyrosine across the brush border averaged 37.5 nmol X cm-2 X h-1. Omission of Na decreased influx by 60%, indicating that tyrosine influx occurs, at least in part, by a Na-coupled process. Ouabain inhibited influx by 80%. Inhibition of brush border Na+-K+-2Cl- cotransport by bumetanide, 8-bromo-cyclic GMP, or Cl replacement stimulated tyrosine influx 2.5- to 4-fold. However, atriopeptin III, which also inhibits Na+-K+-2Cl- cotransport, did not stimulate tyrosine influx. Cyclic AMP, which does not appear to inhibit ion cotransport, did not stimulate tyrosine influx. Both cyclic GMP and bumetanide also stimulated the net mucosa-to-serosa tyrosine flux (43 and 29%, respectively) and increased the cellular concentration of tyrosine by 50%. Thus tyrosine's influx is increased to a greater extent than is its transmural flux or its cellular concentration, suggesting that the main change occurs at the brush border and represents large increases in both influx and efflux of tyrosine across this membrane.

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