title: Dependence of Cr-EDTA absorption from the rumen on luminal osmotic pressure.
abstract: A method for the measurement of [51Cr]EDTA absorption from the ventral sac of the rumen with an error of the order of +/-10% is described. When a solution present in the rumen was hypotonic or isotonic, the absorption rate of [51Cr]EDTA expressed as a clearance was about 0.2 ml/min. This gave rise to negligible errors when [51Cr]EDTA was used as an unabsorbed marker to calculate net water movements. When the osmotic pressure in the rumen exceeded that of plasma by 30-40 mos-mol/kg, the absorption rate of [51Cr]EDTA appeared to be related to the degree of hypertonicity. Absorption rates as high as 8 ml/min were observed within a range of osmotic pressures normally encountered postprandially in the rumen. Under hypertonic conditions, a correction for the absorption of this large anion was necessary if passage of water into the lumen were not to be systematically overestimated.
mesh_terms: D000042:Absorption; D000818:Animals; D002417:Cattle; D002860:Chromium Radioisotopes; D004492:Edetic Acid / Q000378:metabolism*; D005260:Female; D008353:Mannitol; D009997:Osmotic Pressure; D012417:Rumen / Q000378:metabolism*; D012965:Sodium Chloride
chemical_list: D002860:Chromium Radioisotopes; D008353:Mannitol; D012965:Sodium Chloride; D004492:Edetic Acid