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EFFECT OF INTRARUMINAL SODIUM AND POTASSIUM CONCENTRATIONS AND OF THE TRANSMURAL POTENTIAL DIFFERENCE ON MAGNESIUM ABSORPTION FROM THE TEMPORARILY ISOLATED RUMEN OF SHEEP
Author(s) -
Martens H.,
Blume Ingrid
Publication year - 1986
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0144-8757
DOI - 10.1113/expphysiol.1986.sp002999
Subject(s) - potassium , magnesium , sodium , chemistry , rumen , absorption (acoustics) , barium , zoology , inorganic chemistry , food science , biology , materials science , organic chemistry , fermentation , composite material
The net absorption of magnesium from the temporarily isolated and washed reticulo‐rumen of sheep has been studied using buffer solutions with different sodium, potassium and chloride concentrations. An increased potassium concentration led to an increased potential difference (p.d.) and a decreased magnesium absorption. The exchange of chloride in the buffer solutions with sulphate (at constant sodium and potassium concentrations) caused a significant increase of the p.d. and again a reduced net magnesium absorption indicating that the p.d. is an important factor associated with decreased net magnesium absorption. The replacement of sodium with lithium (at constant potassium concentrations) did not influence the net magnesium absorption. It is concluded that the low apparent availability of magnesium after an oral load of potassium is mainly caused by the high transmural potential difference across the rumen wall under such feeding conditions. However, the presented data cannot rule out an effect of potassium per se independent of the effect of the p.d.