Active potassium transport by rabbit descending colon epithelium

Wills, N. K.; Biagi, B. A.

doi:10.1007/bf01870886

Cited by 87 publications

(29 citation statements)

References 17 publications

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“…Studies of colonic potassium transport in rat, rabbit, and guinea pig have established that active K absorption is present in the distal, but not proximal, large intestine and is energized by an apical membrane K-ATPase (9,10,(17)(18)(19). Both active K absorption and K-ATPase activity are partially inhibited by ouabain, and functional studies strongly suggest that there may be two active K absorption/K-ATPase systems, e.g., one that is inhibited by ouabain and the other that is ouabain insensitive (10,11).…”

Section: Discussionmentioning

confidence: 99%

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Functional expression and segmental localization of rat colonic K-adenosine triphosphatase.

Lee¹,

Rajendran²,

Mann³

et al. 1995

J. Clin. Invest.

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A putative cDNA for the colonic K-ATPase has recently been cloned (Crowson, M. S., and G. E. Shull. 1992. J. Biol. Chem. 267:13740-13748). Considerable evidence exists that there are two K-ATPases and active K absorptive processes in the rat distal colon: one that is ouabain sensitive and the other ouabain insensitive. The present study used the baculovirus expression system to express K-ATPase activity in insect Spodoptera frugiperda (Sf 9) cells and a polyclonal antibody (M-1), developed against a fusion protein produced from the 327 nucleotide fragment from 5' coding region of the putative K-ATPase cDNA, to identify the specific localization of the K-ATPase protein. K-ATPase activity (28.7+1.2 nmol inorganic phosphate/mg protein min) was expressed in plasma membranes isolated from Sf 9 cells infected with baculovirus containing recombinant DNA with the putative K-ATPase cDNA. Km for K for the K-ATPase was 1.2 mM. The expressed K-ATPase activity was not inhibited by ouabain (1 mM); while the K; for vanadate inhibition was 8.3 ,uM. Western blot analysis with the M-1 antibody identified a 100-kD protein in apical membranes prepared from distal, but not proximal, rat colon. Immunohistochemical studies with M-1 antibody localized K-ATPase only in the apical membrane of surface cells, while an mAb (c464.6) against Na,K-ATPase localized basolateral membranes of both surface and crypt cells of rat distal colon. In conclusion, the putative K-ATPase cDNA encodes an ouabain-insensitive K-ATPase that is present only in the apical membrane of surface cells of rat distal colon. (J. Clin.

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Section: Discussionmentioning

confidence: 99%

“…(Table I) with Ki's of 8.3 and 13.6 MM, respectively (data not shown). In addition, SCH 28080, a potent inhibitor of gastric H,K-ATPase activity, inhibited K-ATPase activity in Sf 9 cells and colonic apical membranes by 18 and 24%, respectively (Table I).…”

Section: Methodsmentioning

confidence: 98%

Functional expression and segmental localization of rat colonic K-adenosine triphosphatase.

Lee¹,

Rajendran²,

Mann³

et al. 1995

J. Clin. Invest.

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“…This has been suggested to be mediated by (Na+ +K+)-ATPase, since ouabain added to the serosal side inhibits active K+ secretion (WILLS and BIAGI, 1982;MCCABE et al, 1982MCCABE et al, , 1984PLASS et al, 1986;SULLIVAN and SMITH, 1986). For (Na+ +K+)-ATPase to support the K+ uptake, a continuous supply of Na + into the cell might be necessary.…”

Section: Discussionmentioning

confidence: 99%

“…It is proposed that K+ uptake across the basolateral membrane is active and mediated by (Na+ +K+)-ATPase since ouabain added to the serosal side has been shown to inhibit K + secretion (WILLS and BIAGI, 1982;MCCABE et al, 1982MCCABE et al, , 1984PLASS et al, 1986;SULLIVAN and SMITH, 1986). In addition, the increases in K + secretion induced by dietary-K + loading or Na + deprivation are associated with an increase in (Na + + K + )-ATPase activity of colonic epithelium (FISI-mR et al, 1976;HAYSLETT et al, 1980;KASHGARIAN et al, 1980).…”

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confidence: 99%

Potassium secretion in the guinea pig distal colon.

Ishida

Suzuki

1987

Jpn.J.Physiol

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Active K + secretion in guinea pig distal colon was studied in vitro in Ussing chambers. Changes in short-circuit current (ISO), transepithelial conductance (Ge), and the unidirectional flux of 42K from serosa to mucosa (J) were determined under a variety of physiological and pharmacological conditions. Mucosal tetraethylammonium (TEA) (10 or 30 mM) increased ISO, while it decreased Gt and J m. Seroal bumetanide (10-4 M) also caused an increase in ISO and decreases in Gt and JK,. The effects produced by TEA were abolished in the presence of bumetanide. The increase in ISO caused by bumetanide was greatly reduced by mucosal high-K + conditions. Isoproterenol (10_6 M), a f3-adrenergic agonist, elicited a decrease in ISO and an increase in Gt. Responses to isoproterenol (10 -6 M) were reduced or abolished by mucosal TEA, serosal bumetanide, serosal ouabain (10-4 M), and serosal Na+-or Cl--free conditions. Mucosal high K + also reduced the isoproterenol-induced decrease in ISL. These results suggest that K+ secretion is electrogenic and dependent on the bumetanide-sensitive cotransport in the basolateral membrane. K+ exit across the apical membrane might be conductive and sensitive to TEA. In addition, f3-adrenergic agonists might stimulate K + secretion.

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“…(11) and frog skin (12). Several investigators (3,(13)(14)(15) have reported that the luminal membranes of some segments of the intestinal tract and the distal nephron have a high K+ permeability. These epithelia normally secrete K+ but are capable of active K+ absorption under the appropriate conditions (1-6).…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of K+ Transport in Isolated Turtle Urinary Bladder

Husted¹,

Steinmetz²

1982

J. Clin. Invest.

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A B S T R A C T Transepithelial K+ movement was studied in vitro in the short-circuited turtle bladder by increasing luminal K+ permeability and by inhibiting the basolateral Na/K pump. Luminal addition of amphotericin B caused net K+ secretion (180±52 nmol/ h) compared with net K+ absorption (42±6 nmol/h) in control bladders. Serosal ouabain and luminal amiloride abolished K+ secretion in amphotericin-treated bladders; ouabain restored net absorption (45±16 nmol/h). The direction and rate of net K+ transport are controlled by the relative K+ permeabilities and the Na/K pump sites at the two cell membranes of the epithelium.

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Active potassium transport by rabbit descending colon epithelium

Cited by 87 publications

References 17 publications

Functional expression and segmental localization of rat colonic K-adenosine triphosphatase.

Functional expression and segmental localization of rat colonic K-adenosine triphosphatase.

Potassium secretion in the guinea pig distal colon.

Mechanisms of K+ Transport in Isolated Turtle Urinary Bladder

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