Absorption and secretion of potassium by rabbit descending colon

Plass, Herbert; Gridl, Andrea; Turnheim, Klaus

doi:10.1007/bf00583375

Cited by 31 publications

(32 citation statements)

References 31 publications

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“…(In normal animals bumetanide reduced the small JK to a value equivalent to passive transfer.) In a similar study in rabbit descending colon, both basal and adenosine-stimulated JK were abolished in the absence of serosal Cl or Na, or with serosal furosemide, indicating that only K which enters via the basolateral Na-K-2Cl cotransport is available for K secretion (8).…”

Section: Discussionmentioning

confidence: 84%

“…However, Na-K-2C1 cotransport process could also be involved in K secretion. This possibility is not unlikely because serosal bumetanide or furosemide, inhibitors of Na-K-2C1 cotransport, block prostaglandin E2, epinephrine, and adenosine-induced K secretion in rabbit colon (7,8) and vasoactive intestinal polypeptide-induced C1 secretion in T84 colonic cancer cells (9). Thus, it is not known whether the Na-K-2C1 cotransport contributes to K uptake across the basolateral membrane in aldosterone-induced K secretion, and if so, the relative contribution ofthe Na,K-pump and Na-K-2Cl cotransport to overall K secretion.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of aldosterone-induced potassium secretion in rat distal colon.

Sweiry¹,

Binder²

1989

J. Clin. Invest.

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The role of apical and basolateral membranes in aldosteroneinduced active potassium (K) secretion in rat distal colon was investigated by measuring mucosal-to-serosal (Jm) and serosal-to-mucosal (s.m) 42K fluxes (jueq * h-.* cm-2) across isolated stripped mucosa under short-circuit conditions in normal and secondary-hyperaldosterone animals. In normal colons mucosal tetraethylammonium (TEA; 30 mM) or barium (Ba; 5 mM), but not cesium (Cs; 15 mM), reduced J,. without affecting J.s. In aldosterone animals (a) net K secretion (-0.54±0.11) was converted to net K absorption (0.63±0.15) by mucosal TEA, which produced a marked reduction in J,.

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Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Characterization of aldosterone-induced potassium secretion in rat distal colon.

Sweiry¹,

Binder²

1989

J. Clin. Invest.

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“…This decrease in ISO is mostly due to activation of electrogenic K + secretion, since the mucosal high-K + condition abolished the decrease in ISL. In rabbit and guinea pig colons f3-adrenergic agonist, which elevates intracellular cyclic AMP concentration, has been shown to elicit a decrease in ISO associated with an increase in G~, both of which are due to stimulation of K+ secretion (SMITH and MCCABE, 1986;PLASS et al, 1986;HALM and FRIZZELL, 1986;ISHIDA and SUZUKI, 1987). The decreases in 15C together with the G, increase after a peak configuration in response to VIP or prostaglandin E2 (Fig.…”

Section: Discussionmentioning

confidence: 88%

“…In the rabbit and the guinea pig colon, electrogenic K+ secretion, which is stimulated by /3-adrenergic agonist (probably mediated by cyclic AMP), has been demonstrated (HALM and FRIZZELL, 1986;PLASS et al, 1986;SMITH and MCCABE, 1986;ISHIDA and SuzuKI, 1987). It is likely that the decrease in ISO induced by 8-bromocyclic AMP as shown above is mainly due to enhancement of K+ secretion.…”

Section: Mucosal High-k+ Conditionmentioning

confidence: 86%

Synergism between calcium-mediated and cyclic AMP-mediated activation of chloride secretion in isolated guinea pig distal colon.

Yajima

Suzuki

1988

Jpn.J.Physiol

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Synergistic effects of Cat +-mediated secretagogues and cyclic AMP-mediated secretagogues on Cl -secretion by guinea pig distal colon were studied in vitro using Ussing chambers. Short-circuit current (ISO) and bidirectional fluxes of Z2Na + and 3601-were measured. Bethanechol (10-4 M, a Cat+-mediated secretagogue) caused an increase in ISO, which was enhanced 4-20 fold when the tissue was pretreated with prostaglandin E2 (10-'-10-6 M), vasoactive intestinal polypeptide (5 x 10-9-10_8 M) (cyclic AMP-mediated secretagogues), or 8-bromocyclic AMP (5 x 10-4-2 x 10 -3M). Measurement of 3601 flux showed that the increase in ISO in the presence of both 8-bromocyclic AMP and bethanechol resulted principally from increased Cl-secretion. On the other hand, the net absorptive flux of 22Na was not influenced under these conditions. Potentiation of the increase in ISO was also elicited by the combination of A23187 (5 x 10_6 M) and 8-bromocyclic AMP (10-3 M). The results are consistent with the notion that simultaneous activation of the cyclic AMP-mediated and Cat+-mediated systems produces a synergistic increase in colonic Clsecretion.

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“…The colonic (H+-K+)-ATPase activity was used as a marker enzyme for apical membranes. Evidence for the presence of this enzyme in the apical membrane of the rabbit colon has been obtained from active K+ absorption studies (7,8). Moreover, this marker en zyme has been successfully used to isolate apical membrane fragments from surface cells of rabbit and rat distal colon (3, 4).…”

Section: Discussionmentioning

confidence: 99%

Apical Membrane Isolation of Surface and Crypt Cells from Rabbit Distal Colon

Abrahamse

Bridges

Jong

et al. 1996

Analytical Biochemistry

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Surface and crypt cells of rabbit distal colon were separately isolated, and amilo ride-sensitive 22Na+ up take could only be dem onstrated in a crude membrane fraction derived from surface cells. For purification of apical membranes of surface and crypt cells (H+-K+)-ATPase and alkaline phosphatase w ere used as puta tive apical membrane markers. Apical membranes of surface cells were isolated after mild homogenization, low speed centrifugation, and subsequent fraction ation on a Percoll density gradient. Apical membranes o f crypt cells were collected after more vigorous ho m ogenization, followed by high speed centrifugation, and fractionation on a Percoll gradient. The mammalian colon contributes to the electro lyte homeostasis of the body. Under normal condi tions, the distal colon absorbs Na+, Cl", and water, whereas HCO^ and K+ are secreted (1). To study the mechanisms involved in translocating ions across the apical and basolateral membrane, purified mem brane vesicles from either pole of the epithelial cell have been recognized as powerful tools. However, the isolation of plasma membrane vesicles from rabbit distal colon is fraught with difficulties. The presence of mucus, which tends to aggregate membranes dur ing homogenization, and the strong attachment of cells to the basement membrane severely hamper the isolation of basolateral and apical plasma membrane vesicles. The lack of an accepted marker and the ab sence of a brush border are additional problems that are encountered during isolation of apical mem branes (2-4).Nevertheless, Wiener e ta l (2) developed a method to isolate simultaneously basolateral membrane vesi cles from rabbit distal colonic surface and crypt cells. In addition, procedures for isolating apical mem brane vesicles from rabbit distal colon have also been described (3, 4). However, in the latter isolation pro cedures, only surface cells were used. Therefore, the aim of the present study was to develop a method for the simultaneous isolation of apical membrane vesicles from surface and crypt cells. To this end, the colonic surface cells were isolated as described by Gustin and Goodman (3) and crypt cells were col lected through mucosal scraping (2). The apical mem brane of rabbit colonic surface and crypt cells con tains a gastric-like (H+-K+)-ATPase that mediates active K+ absorption by this tissue (5-8). Therefore, this enzyme was used as a marker for apical mem branes of both cell types. The (H+-K+)-ATPase was measured as K+-stimulated ouabain-insensitive ATPase and as K+-stimulated SCH 28080-sensitive ATPase, since SCH 28080 is a specific inhibitor of the gastric (H+-K*)-ATPase (9). In addition, alkaline phosphatase activity was used as a putative marker. Fractions in which both markers were enriched were identified as purified apical membrane vesicles from surface and crypt cells. The usefulness of these iso lated fractions was evaluated by fusing the vesicles 112

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Absorption and secretion of potassium by rabbit descending colon

Cited by 31 publications

References 31 publications

Characterization of aldosterone-induced potassium secretion in rat distal colon.

Characterization of aldosterone-induced potassium secretion in rat distal colon.

Synergism between calcium-mediated and cyclic AMP-mediated activation of chloride secretion in isolated guinea pig distal colon.

Apical Membrane Isolation of Surface and Crypt Cells from Rabbit Distal Colon

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