Uptake of dehydroepiandrosterone sulphate into human breast cyst fluids

7-alpha tritiated dehydroepiandrosterone (DHA) sulphate was infused over a 24-h period to five patients with multiple breast cysts and over 48 h to 11 patients. Cysts were aspirated and blood taken at various times during the infusion and during a 2-year follow-up period. Plasma levels of radioactivity remained constant during the course of infusion whereas radioactivity in cyst fluids increased with time of infusion and by 20 h levels of radioactivity in cyst fluid were frequently greatly in excess of those in plasma. This active uptake of radioactivity was evident in four of five patients infused for 24 h and in all 11 patients studied over 48 h. Not all cyst fluids demonstrated active uptake. This was only seen in Type I cysts (apocrine-identified by electrolyte composition) and not in Type 11 cysts. Cysts were aspirated from nine patients during the 2-year follow-up period. All cysts contained levels of radioactivity beyond that detected in plasma (which was negligible) and in three patients levels of radioactivity from cysts aspirated from follow-up were higher than the levels found in cyst fluids aspirated during the period of infusion. Even at 2 years after infusion detectable levels of radioactivity were present in breast cysts fluids. Characterization of the radioactivity showed that it was associated with DHA-sulphate. This study has demonstrated active uptake of DHA-sulphate into Type I cyst fluids. Although the clinical significance remains to be determined, it demonstrates that breast epithelium may actively concentrate and retain substances from plasma. This means that breast epithelium may be exposed to high concentrations of xeno-biologicals for prolonged periods