Premium
Osteoblast cells (MG‐63 and HOS) have aromatase and 5α‐reductase activities
Author(s) -
Shimodaira Kazuhisa,
Fujikawa Hiroshi,
Okura Fumiya,
Shimizu Yukiko,
Saito Hiroshi,
Yanaihara Takumi
Publication year - 1996
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549600201111
Subject(s) - aromatase , androstenedione , osteoblast , chemistry , reductase , endocrinology , medicine , androgen , enzyme , biochemistry , biology , hormone , in vitro , cancer , breast cancer
Both aromatase and 5α‐reductase activities were found by whole‐cell assay in osteoblast‐like cells, MG‐63 and HOS. Aromatase activity was measured by the [3H] water release method, and the formation of 5α‐androstanedione from androstenedione was expressed as 5α‐reductase activity. When CGS16949A, an inhibitor of aromatase, was added to the incubation medium at a concentration of 2 × 10‐9 M, sufficient to completely inhibit placental aromatase activity, only 63% to 68% inhibitions were observed. When progesterone, a competitive inhibitor of 5α‐reductase, was added at a concentration of 10‐5 M, 28% to 40% inhibitions were recorded. Because the release of [3H] from [1β‐3H] androstenedione into water by 5α‐reductase is reported, results from the present study suggest that the measurement of aromatase activity in osteoblasts by the [3H] water release method may overestimate aromatase activity owing to the inclusion of 5α‐reductase activity. The results also suggest that osteoblast cells may play an important role in bone metabolism by transforming androgens into estrogens and more biologically active androgen derivatives.