title: Perichondrial localization of ETA receptor in rat tracheal and xiphoid cartilage and in fetal rat epiphysis.
abstract: 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.
authors.affiliation: Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: K M
authors.initials: KM
authors.lastname: Lodhi
authors.forename: H
authors.initials: H
authors.lastname: Sakaguchi
authors.forename: S
authors.initials: S
authors.lastname: Hirose
authors.forename: S
authors.initials: S
authors.lastname: Shibabe
authors.forename: H
authors.initials: H
authors.lastname: Hagiwara
mesh_terms: 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*
chemical_list: D016232:Endothelins; D017466:Receptors, Endothelin; D013936:Thymidine