K+ transport by rat colon: adaptation to a low potassium diet.
In: The American journal of physiology, Jg. 250 (1986-03-01), Heft 3 Pt 2, S. F483-7
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Zugriff:
Recent studies with the isolated perfused rat kidney have demonstrated the existence of an intrinsic renal adaptation to conserve K+ in response to ingestion of a low K+ diet for 3 days. To determine whether the colon alters its K+ transport properties in a similar fashion, we measured transmural 86Rb fluxes across sheets of distal colonic epithelium under short-circuit conditions. Preliminary studies using a double-isotope technique demonstrated that 86Rb and 42K fluxes were similar; therefore 86Rb flux was considered equivalent to K+ flux. The distal half of the colon from each rat was divided into two segments, referred to as early and late distal colon. Experiments were carried out using rats fed a K+ -free, control (0.15 mmol/g), and high K+ (1.13 mmol/g) powdered diet of otherwise identical electrolyte content. Net K+ secretion (Jnet) by the early distal colon was reduced from 0.45 in the controls to -0.02 mueq X cm-2 X h-1 by a low K+ diet as a result of a decrease in serosal-to-mucosal flux (Jsm), with no change in mucosal-to-serosal flux (Jms). Conductance (GT) and short-circuit current (Isc) were unchanged. Jnet by the late distal colon averaged 0.17 in the controls and 0.01 mueq X cm-2 X h-1 with a low K+ diet, but this difference was not significant statistically. In comparison with the controls, a high K+ diet had no effect on Jnet by the early distal colon (0.48 mueq X cm-2 X h-1) but increased Jnet by the late distal colon substantially (0.77 mueq X cm-2 X h-1).(ABSTRACT TRUNCATED AT 250 WORDS)
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K+ transport by rat colon: adaptation to a low potassium diet.
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Autor/in / Beteiligte Person: | Tannen, RL ; Marino, R ; Dawson, DC |
Zeitschrift: | The American journal of physiology, Jg. 250 (1986-03-01), Heft 3 Pt 2, S. F483-7 |
Veröffentlichung: | Bethesda, MD : American Physiological Society ; <i>Original Publication</i>: Washington [etc.] American Physiological Society., 1986 |
Medientyp: | academicJournal |
ISSN: | 0002-9513 (print) |
DOI: | 10.1152/ajprenal.1986.250.3.F483 |
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