Studies of the metabolism of dehydroepiandrosterone (DHA) by cultured human adipose stromal cells revealed that the most abundant metabolite detected by HPLC was a polar compound accounting for up to 45% of total radioactivity. This metabolite was isolated by chromatography on Lipidex 5000 from the culture medium of breast adipose stromal cells cultured with unlabelled DHA (5 microM) and identified by combined capillary gas chromatography and mass spectrometry as 7 alpha-hydroxydehydroepiandrosterone (7 alpha-OHDHA). In breast adipose stromal cells, the conversion of DHA to 7 alpha-OHDHA was linear from a substrate concentration of 10 nM to 1 microM. At 1 microM substrate concentration, the formation of 7 alpha-OHDHA in four patients ranged from 6.1 to 22.5 ng/10(5) cells/24 h. Incubations carried out in primary culture and up to the fifth subculture revealed continued formation of 7 alpha-OHDHA. Adipose stromal cells from abdomen, flank and perinephric fat also produced 7 alpha-OHDHA from DHA. These studies have shown that 7 alpha-OHDHA is a major metabolite of DHA in human adipose stromal cells. The variability from patient to patient and the magnitude of this conversion suggests that this pathway may play an important role in the peripheral metabolism of DHA.