Potassium transport across guinea pig distal colon

Conference · Wed Mar 05 00:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7189472

Rechkemmer, G; Halm, D R; Frizzell, R A

Active absorption and secretion of K was studied by measuring bidirectional /sup 42/K fluxes across short-circuited guinea pig distal colon. Tissues were pretreated with mucosal (m) and serosal (s) indomethacin (1 ..mu..M) and amiloride (0.1 mM, m) to suppress spontaneous, electrogenic Cl secretion and Na absorption. Under these conditions, the short-circuit current (I/sub sc/) was 0.4 ..mu..eq/cm/sup 2/h while electroneutral K absorption was 2.8 ..mu..eq/cm/sup 2/h. Epinephrine (5 ..mu..M, s) stimulated electrogenic K secretion, reducing net K absorption to 1.3 ..mu..eq/cm/sup 2/h. Bumetanide (0.1 mM, s) abolished this K secretion and restored K absorption to control values, suggesting mechanistic similarities between K and Cl secretion. K absorption was inhibited 40% by the gastric H/K ATPase inhibitor, omeprazole (0.1 mM, m), and was abolished by ouabain (0.1 mM, m). Neutral K absorption does not appear to be mediated by an apical membrane Na/K pump since: the effect of mucosal ouabain on K absorption does not require the presence of mucosal or serosal Na, unidirectional Na fluxes are not influenced by mucosal ouabain, and K absorption is not affected when Na absorption is abolished by amiloride. Net K transport is determined by the balance between electroneutral K absorption and electrogenic K secretion. The ouabain sensitivity of K absorption suggests that colonic H/K ATPase differs from its gastric counterpart.

• Research Organization: Univ. of Alabama, Birmingham
• OSTI ID: 7189472
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
POTASSIUM
MEMBRANE TRANSPORT
SECRETION
ABSORPTION
ADRENALINE
ATP-ASE
GUINEA PIGS
LARGE INTESTINE
OUABAIN
POTASSIUM 42
TRACER TECHNIQUES
ACID ANHYDRASES
ADRENAL HORMONES
ALKALI METAL ISOTOPES
ALKALI METALS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
DIGESTIVE SYSTEM
DRUGS
ELEMENTS
ENZYMES
GASTROINTESTINAL TRACT
GLYCOSIDES
HORMONES
HOURS LIVING RADIOISOTOPES
HYDROLASES
INTERMEDIATE MASS NUCLEI
INTESTINES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
METALS
NEUROREGULATORS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHOSPHOHYDROLASES
POTASSIUM ISOTOPES
RADIOISOTOPES
RODENTS
STEROID HORMONES
STROPHANTHINS
SYMPATHOMIMETICS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques