Effect of azodisal sodium on the distribution of a transit marker in the small bowel of the fasted rat.

The effect of azodisal sodium (ADS) on the transit of a radioactive marker in the small bowel was compared with that of 5-ASA and sulfasalazine (SASP). The bile-excreted radiopharmaceutic 99mTc-HIDA was infused intravenously for 1 h into conscious rats with an intact alimentary tract and the radioactivity along the excised gastrointestinal specimen was subsequently determined. After administration of ADS (12.5 mg/rat), 5-ASA and SASP, the distribution of radioactivity was characterized by localized peaks of radioactivity separated by fairly long empty regions. As judged from experience this pattern represents the fasting state under control conditions. Administration of ADS (60 and 120 mg/rat) resulted in a distribution along the small bowel without any apparent peaks or empty regions. The transport rate of the front of the tracer was enhanced by ADS at higher doses but not by 5-ASA or SASP. Intravenous administration of ADS did not affect the transit, indicating the importance of the presence of ADS in the gut lumen. Prostaglandin release does not seem to be a probable mediating mechanism since pretreatment with indomethacin did not abolish the effect of ADS on the interdigestive transit pattern.