Peer-Reviewed Journal Details
Mandatory Fields
McNamara, B,Winter, DC,Cuffe, J,Taylor, C,O'Sullivan, GC,Harvey, BJ;
2000
December
British Journal of Pharmacology
Rapid activation of basolateral potassium transport in human colon by oestradiol
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Optional Fields
oestradiol non-genomic potassium transport Na+/H+ exchange human colon RAT DISTAL COLON ION-TRANSPORT STEROID-HORMONES RABBIT COLON ALDOSTERONE 17-BETA-ESTRADIOL ABSORPTION MECHANISM CHANNELS NEURONS
131
1373
1378
1 We investigated the effect of oestradiol on basolateral potassium channels in human colonic epithelium.2 Ion transport was quantified using short circuit current (I-sc) measurements of samples mounted in Ussing chambers. Serosal K transport was studied using nystatin permeabilization of the apical membrane. Intracellular pH changes were quantified using spectroflouresence techniques.3 Experiments were performed with either 10 nM or 1 muM Ca2+ in the apical bathing solution. With 10 nM Ca2+ in the apical bathing solution addition of oestradiol (1 nM) to the basolateral bath produced a rapid increase in current (DeltaI(K) = 11.2 +/- 1.2 muA.cm(-2), n = 6). This response was prevented by treatment of the serosal membrane with tolbutamide (1 muM). With 1 muM Ca2+ in the apical bathing solution addition of oestradiol produced a rapid fall in current (DeltaI(K)=-12.8+/-1.4 muA.cm(-2)), this response was prevented by treatment of the basolateral membrane with tetra-pentyl-ammonium (TPeA). These responses were rapid and occurred independently of protein synthesis. 44 Inhibition of basolateral Na+/H+ exchange with either amiloride or a low sodium bathing solution prevented this response. These responses were prevented by inhibition of protein kinase C (PKC) with bis-indolyl-maleimide. 55 Oestradiol (1 nM) produced a rapid intracellular alkanization (mean increase=0.11 pH units; n=6; P<0.01). 66 These results suggest that oestradiol rapidly modulates serosal K transport in human colon. These effects depend upon intact Na+/H+ exchange and protein kinase C. We propose a nonclassical, possibly membrane linked, mechanism for oestradiol action in human colonic epithelium.
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