Metabolism of all-trans-retinoic acid in rat testis.

The metabolism of all-trans-[15-14C]retinoic acid in vitamin A-adequate or vitamin A-deficient rats fed retinoic acid was studied following intratesticular injection. Analysis of testicular metabolites by HPLC at 1, 6, and 24 h demonstrated that the retinoic acid was isomerized to 13-cis-retinoic acid and metabolized to polar metabolites in both groups of rats at all time periods. However, polar metabolites predominated in the testes of the vitamin A-deficient rats. At 24 h the total radioactivity remaining in the testis was much lower in the testes of vitamin A-deficient rats than in normal animals suggesting a faster rate of metabolism of all-trans-retinoic acid in these rats.