Immunohistochemical detection of activin A in osteoclasts.
Production of a member of transforming growth factor-beta (TGF-beta) superfamily, activin A, was examined in the bone tissue by using reverse transcriptase polymerase reaction. As a result, specific bands were detected showing the presence of activin A mRNA in the bone tissues. In order to localize the production site of activin A in the bone tissues, we tried to immunolocalize activin A in fetal mouse calvaria cultured in a medium containing fetal calf serum, 1 alpha-25(OH)2 vitamin D2 and parathyroid hormone. In these cultured calvaria, bone tissues including bone-resorbing osteoclasts in vitro were observed. Positive staining demonstrating the presence of activin A resided inside of the multinucleated cells in the bone resorbing lacunae, suggesting the production of activin A in osteoclasts. Activin A was also localized immunohistochemically in the osteoclast-like multinucleated cells developed in vitro. These results suggest that osteoclast produce activin in the bone tissues and that activin may play some roles by autocrine and/or paracrine manner in bone metabolisms.
Hosoi
T
T
Department of Geriatrics, Faculty of Medicine, University of Tokyo, Japan.
Inoue
S
S
Hoshino
S
S
Ouchi
Y
Y
Orimo
H
H
D028341:Activins; D000818:Animals; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells; D002467:Cell Nucleus / Q000648:ultrastructure; D018920:Coculture Techniques; D007150:Immunohistochemistry; D007265:Inhibins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D010010:Osteoclasts / Q000378:metabolism* / Q000648:ultrastructure; D016133:Polymerase Chain Reaction; D051381:Rats; D017208:Rats, Wistar; D012886:Skull / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D014158:Transcription, Genetic
D028341:Activins; D007265:Inhibins