Research Areas



  • Sample Type Serum, Plasma, Urine, Fecal Extracts, Tissue Culture Media
  • Species Estrone-3-sulfate (E1S) is identical across species
  • Stability Liquid 4°C Stable Reagents
  • Sensitivity 26.4 pg/mL
  • Time to Answer 2.5 Hours
  • Samples/Kit 40 or 232 in Duplicate
  • Readout Colorimetric, 450 nm
  • Standard Curve
  • Description

    Estrone-3-sulfate (E1S) is synthesized in the fetal or cotyledonary portion of the placentome. Estrone sulfate, which is present in plasma at a higher concentration than either unconjugated estrone or estradiol in nonpregnant women and normal men, appears to originate almost entirely from a conjugation of estrone and converted estradiol in non-glandular tissues. Estrone sulfate is quantitatively the most important circulating estrogen. Breast tumors contain sulfatase activity and can convert estrone sulfate into estradiol. Cryptorchidism, where one or both testicles fail to descend is considered to be a prevalent defect in horses. Bilaterally cryptorchid stallions do not produce viable spermatozoa but often exhibit normal secondary sexual characteristics. Several investigators have suggested measuring testosterone and estrone sulfate serum levels as reliable diagnostic aids for the condition.