On the occurrence and transport of estriol-3-sulfate in human breast cyst fluid: the metabolic disposition of blood estriol-3-sulfate in normal women.

The high concentration of estriol-3-sulfate (E3-3S) in human breast cyst fluid has been confirmed in 14 women with multiple cysts. The concentrations of E3-3S found in individual cysts drained within a short time span from the same patient were variable, the ratios ranging from unity to 40. After the iv administration of [14C]estriol or [3H]E3-3S, only minor accumulation of either isotope was detected in the cyst fluids aspirated 6.5-30 h later. Since surprisingly small amounts of isotopes were found in blood, the metabolism of [3H]E3-3S was studied in 2 normal women. The test compound was injected iv, and blood samples were taken at intervals up to 7.5 h. In addition, total urine was collected for 3 days. The blood clearance of [3H]E3-3S was rapid, with the half-life ranging from 15-30 min. However, E3-3S was only a minor component of the urine, indicating rapid tissue extraction and metabolism rather than renal excretion for the compound. The studies indicate that E3-3S of human breast cyst fluid does not equilibrate rapidly with other body pools and that its uptake, if any, from the blood would be against a gradient.