Quantitative determination of gastrointestinal bleeding in rats

A method for the quantitative determination of gastrointestinal bleeding in rats is described. The method is dependent upon the extraction of blood from stomach and intestinal contents, or from feces, of rats. The blood (heme) in the dry extract is measured spectrophotometrically after conversion to pyridine-hemochromogen. The heme concentration is computed from the spectrophotometric scans of the dithionate-reduced versus the oxidized pyridine hemochromogen. The current method is suitable for the quantitative determination of acute and chronic gastrointestinal blood loss. It is also experimentally useful as a pharmacological screening technique and for quantitative comparisons of drug-induced gastrointestinal bleeding. Contrary to existing methods, this method is easier, reproducible, accurate, less expensive, less time consuming, less risky (no radioactive material is required), useful in providing some information about the site of gastrointestinal bleeding, and is not influenced by changes in bile formation and flow.