title: Steroid sulfatase activity in osteoblast cells.
abstract: We have demonstrated steroid sulfatase activity in osteoblast cells and characteristics of the enzyme were also investigated. Cell free homogenate of rat osteoblast cell line, UMR106-01 and human osteoblast cell lines, MG-63, HOS were incubated with [3H] dehydroepiandrosterone-sulfate (DHEA-sulfate) or [3H] estrone-sulfate (E1-sulfate). The formation of DHEA or E1 from the corresponding substrate was identified by crystallization to constant specific activity. Michaelis constant (K(m)) for DHEA-sulfate was estimated as 2.1 x 10(-8)M in UMR106-01, 7.4 x 10(-7)M in MG-63, 5.8 x 10(-7)M in HOS and that for E1-sulfate was 4.1 x 10(-7)M, 3.0 x 10(-7)M, 9.8 x 10(-7)M, respectively. The expression of steroid sulfatase messenger ribonucleic acid in human osteoblast cells, HOS and MG-63 was first demonstrated by reverse transcription-polymerase chain reaction. The existence of steroid sulfatase in human and rat osteoblast cells suggests that osteoblast cells have the capacity to convert circulating sulfo-conjugated steroids to more active androgens and estrogens. This may indicate an important role of bone in facilitating hormonal action.
authors.affiliation: Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Fujikawa
authors.forename: F
authors.initials: F
authors.lastname: Okura
authors.forename: Y
authors.initials: Y
authors.lastname: Kuwano
authors.forename: A
authors.initials: A
authors.lastname: Sekizawa
authors.forename: H
authors.initials: H
authors.lastname: Chiba
authors.forename: K
authors.initials: K
authors.lastname: Shimodaira
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: T
authors.initials: T
authors.lastname: Yanaihara
mesh_terms: D000818:Animals; D001192:Arylsulfatases / Q000235:genetics / Q000378:metabolism*; D019314:Dehydroepiandrosterone Sulfate / Q000378:metabolism; D004970:Estrone / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D010006:Osteoblasts / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D043266:Steryl-Sulfatase; D014407:Tumor Cells, Cultured
chemical_list: D012333:RNA, Messenger; D004970:Estrone; D019314:Dehydroepiandrosterone Sulfate; D001192:Arylsulfatases; D043266:Steryl-Sulfatase; C017296:estrone sulfate