Metabolism of papaverine. I. Identification of metabolites in rat bile.

1. After hydrolysis with glusulase of bile from rats treated with papaverine, four metabolites (A, B, C and D) were separated. 2. The structures A, B and C were established as monodemethylated compounds, 4'-desmethyl-, 7-desmethyl-, and 6-desmethylpapaverine, respectively. 3. D was formed from papaverine by bis-desmethylation. Since it was found in cat bile after administering either A or C, but not B, it was identified as 4', 6-desmethylpapaverine.