Perichondrial localization of ETA receptor in rat tracheal and xiphoid cartilage and in fetal rat epiphysis.
Autoradiographic studies using 125I-labeled endothelin-1 (ET-1) on sections of rat cartilage tissues, including the trachea, xiphisternum, and fetal rat epiphysis, revealed dense localization of endothelin receptors in the perichondrium. In contrast, the binding of ET-1 was not detected in the chondrocytes, cartilage matrix, and other connective tissues of the cartilage tissues tested. The perichondrial binding of 125I-ET-1 was completely abolished with BQ-123 [an endothelin receptor subtype A (ETA) antagonist] but not with BQ-3020 (an ETB agonist), and we demonstrated the perichondrial localization of ETA receptors. [3H]thymidine incorporation in vitro was significantly increased in rat xiphoid cartilage tissues exposed to ET-1. These findings suggest that the ET-1/ETA receptor system plays an important role in regulating cartilage metabolism and endochondral bone formation.
Lodhi
K M
KM
Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan.
Sakaguchi
H
H
Hirose
S
S
Shibabe
S
S
Hagiwara
H
H
D000818:Animals; D002356:Cartilage / Q000378:metabolism*; D016232:Endothelins / Q000494:pharmacology; D004838:Epiphyses / Q000196:embryology* / Q000378:metabolism; D005333:Fetus / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D017466:Receptors, Endothelin / Q000145:classification / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism; D014018:Tissue Distribution; D014132:Trachea / Q000378:metabolism*; D014989:Xiphoid Bone / Q000378:metabolism*
D016232:Endothelins; D017466:Receptors, Endothelin; D013936:Thymidine