Regulation of @entity6478 -sensitive electrogenic @entity1372 transport in the XXXX colon by @entity134 hormones.

@entity1667 @entity251 @entity1369 @entity35 @entity1420 @entity1372 @entity6478 @entity53 @entity2819 @entity619 @entity134 @entity972 @entity230
The role of @entity230 in the regulation of colonic @entity1372 transport was examined by infusing @entity230 into adrenalectomized (ADX) @entity35 and evaluating the short-circuit current (ISC) in vitro. @entity6478 -sensitive ISC was induced by @entity1369 and @entity2819 with half-maximal doses (ED50) of 2 and 260 micrograms X kg-1 X h-1), respectively. Synthetic glucocorticoids such as @entity1667 (33 mg/kg) and @entity619 (ED50 = 30 micrograms X kg-1 X h-1) were also effective. Supramaximal doses of @entity1369 (7.5 times ED50) for 24 h increased the total ISC (7-fold), the @entity6478 -sensitive ISC (366-fold), and the conductance (2-fold), as well as the @entity972 -stimulated phosphatase activity (2-fold) (reported previously). Compared with @entity1369 , supramaximal doses of @entity619 (4 times ED50) produced greater increases in the total ISC (15-fold) and the @entity6478 -sensitive ISC (674-fold). In contrast to @entity1369 , @entity619 also increased the @entity6478 -insensitive ISC (3-fold). Glucocorticoid action was not mediated by insulin since the ISC from diabetic ADX @entity35 was increased by @entity619 to a similar extent (11-fold) as in nondiabetic @entity35 . @entity53 , @entity1420 , and @entity251 did not stimulate the colonic ISC of ADX @entity35 . The ED50 values of @entity2819 and @entity1369 , measured in terms of @entity6478 -sensitive @entity1372 transport, produced serum levels that were slightly above those of unstressed, adrenal-intact animals and thus must be considered physiological. It is concluded that at physiological levels both @entity230 may mediate @entity6478 -sensitive @entity1372 transport in the @entity35 colon. However, as judged from changes in serum @entity134 levels, @entity1369 is the physiological regulator of elevated @entity1372 absorption in @entity1372 deficiency.
