title: Low oxygen enhances endothelin-1 (ET-1) production and responsiveness to ET-1 in cultured cardiac myocytes.
abstract: To understand the pathophysiological role of ET-1 in heart, the ET-1 production ability and the responsiveness to ET-1 in cultured neonatal rat cardiac myocytes were compared between high (50%) and low (21%) oxygen atmosphere culture conditions. The amount of immunoreactive ET-1 secreted by the cardiac myocytes into the culture medium was much higher at the low oxygen condition. An analysis of ET-1 binding capacity to the cardiac myocytes revealed that the receptor number of ET-1 was about two-fold at low oxygen culture condition. In fact, an addition of ET-1 (1nM) increased in protein synthesis at the low but not the high oxygen culture condition. Thus, the increase in ET-1 production and responsiveness to ET-1 in the cardiac myocytes at the low oxygen culture condition suggests that autocrine ET-1 might be involved in the maintenance of beating ability in heart at hypoxia.
authors.affiliation: Cell Biology Laboratory, National Institute of Biosciences and Human Technology-Ibaraki, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kagamu
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Arakawa
authors.forename: Y
authors.initials: Y
authors.lastname: Mitsui
mesh_terms: D000818:Animals; D015687:Cell Hypoxia; D002478:Cells, Cultured; D016232:Endothelins / Q000096:biosynthesis* / Q000502:physiology; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017466:Receptors, Endothelin / Q000378:metabolism
chemical_list: D016232:Endothelins; D017466:Receptors, Endothelin