title: A direct assay for oestrone sulphate and its use to investigate the effect of ampicillin on plasma levels of oestrone sulphate.
abstract: A direct radioimmunoassay for measuring plasma levels of oestrone sulphate has been developed using 8-anilino-2-naphthalene sulphonic acid to displace oestrone sulphate from plasma binding proteins. Oestrone sulphate was assayed by using an antiserum raised against glucuronide which cross-reacted 100% with oestrone sulphate. The direct assay gave a good analytical recovery of oestrone sulphate and there was a good correlation (r = 0.82, P less than 0.001) for plasma levels of oestrone sulphate measured by the direct assay and a method involving steroid conjugate extraction and enzyme hydrolysis. The mean (+/- S.D.) plasma level of oestrone sulphate in men was 1100 +/- 280 pg/ml. The effect of taking the antibiotic, Ampicillin, on plasma levels of oestrone sulphate was investigated in four men. Plasma levels of oestrone sulphate were significantly reduced after taking Ampicillin for 5 days. Ampicillin may act to lower plasma levels of oestrone sulphate by reducing the growth of bacteria in the gut or by inhibiting oestrogen sulphotransferase activity.
authors.affiliation: Department of Chemical Pathology, St. Mary's Hospital Medical School, London, United Kingdom.
authors.forename: M J
authors.initials: MJ
authors.lastname: Reed
authors.forename: M M
authors.initials: MM
authors.lastname: Gompels
authors.forename: P A
authors.initials: PA
authors.lastname: Beranek
authors.forename: V H
authors.initials: VH
authors.lastname: James
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D004966:Estrogens, Conjugated (USP) / Q000097:blood*; D004970:Estrone / Q000031:analogs & derivatives* / Q000097:blood; D006801:Humans; D008297:Male
chemical_list: D004966:Estrogens, Conjugated (USP); D004970:Estrone; D000667:Ampicillin; C017296:estrone sulfate