Steroid Sulfatase Activity in Osteoblast Cells

• Published in: Biochemical and biophysical research communications Vol. 231; no. 1; pp. 42 - 47
• Main Authors: Fujikawa, Hiroshi, Okura, Fumiya, Kuwano, Yuzuru, Sekizawa, Akihiko, Chiba, Hiroshi, Shimodaira, Kazuhisa, Saito, Hiroshi, Yanaihara, Takumi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 03.02.1997
• Subjects: Animals; Arylsulfatases - genetics; Arylsulfatases - metabolism; Dehydroepiandrosterone Sulfate - metabolism; Estrone - analogs & derivatives; Estrone - metabolism; Humans; Osteoblasts - enzymology; Polymerase Chain Reaction; Rats; RNA, Messenger - genetics; RNA, Messenger - metabolism; Steryl-Sulfatase; Tumor Cells, Cultured
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1996.6038

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] estronesulfate (E1-sulfate). The formation of DHEA or E1from the corresponding substrate was identified by crystallization to constant specific activity. Michaelis constant (Km) for DHEA-sulfate was estimated as 2.1 × 10−8M in UMR106-01, 7.4 × 10−7M in MG-63, 5.8 × 10−7M in HOS and that for E1-sulfate was 4.1 × 10−7M, 3.0 × 10−7M, 9.8 × 10−7M, 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.