In vitro metabolism and biological activity of all-trans-retinoic acid and its metabolites in hamster trachea.

Isolation and identification of 4-hydroxy- and 4-oxoretinoic acid. In vitro metabolites of all-trans-retinoic acid in hamster trachea and liver

“…Generation of Peak 5. It had previously been demonstrated that [3H]retinoic acid can be metabolized by tracheal organ cultures to several more polar metabolites (Frolik et al, 1978b), the major metabolite regions being designated as peaks 2, 4, and 5. The peak 5 region, showing some biological activity, was chosen for initial identification studies.…”

“…Use of the tracheal organ culture system to generate sufficient quantities of peak 5 for identification proved difficult. Peak 5 metabolites are quickly converted by the trachea to peak 4 region compounds (Frolik et al, 1978b) and therefore never accumulate to any great concentration. In addition, as the concentration of retinoic acid in the medium is increased to obtain a greater quantity of peak 5, toxic levels are soon [3H] Retinoic acid (2.2 X 1CT6 M) was incubated with liver supernatant as described under Experimental Procedure.…”

“…The in vitro tracheal metabolites used for chromatography with the liver peak 5 compounds were obtained from the hamster tracheal organ culture system described previously (Frolik et al, 1978b). The culture medium was extracted with methanol and with butanol-water as described above.…”

“…This technique avoids the complicating effects of absorption, tissue distribution, storage, and excretion. With this method a tissue-dependent metabolism of retinoic acid to several more polar metabolites has been observed (Frolik et al, 1978b). These in vitro metabolites migrated together after LC with either intestinal or urinary metabolites formed in vivo.…”

“…Most previous investigations have examined the in vivo metabolism of retinoic acid. However, recent studies (Frolik et al, 1978b) have focused on the in vitro metabolism of this retinoid by using a tracheal organ culture system that is responsive to retinoids in vitro (Clamon et al, 1974;Sporn et al, 1974). This technique avoids the complicating effects of absorption, tissue distribution, storage, and excretion.…”