title: Sandwich-enzyme immunoassays for endothelin family peptides.
abstract: Sandwich-enzyme immunoassays (sandwich-EIAs) for endothelin-1 (ET-1), endothelin-3 (ET-3), big ET-1, big endothelin-2 (big ET-2), and big endothelin-3 (big ET-3) have been established using two antibodies directed against the N-terminal and C-terminal portions of each ET and big ET. These sandwich-EIAs are sensitive enough to detect 0.1-0.4 pg/well of each ET or big ET with cross-reactivity of less than 1% with other ETs and big ETs (except in the case of the EIA for ET-1, which detects immunoreactivity of ET-2 as well as ET-1). Plasma levels of immunoreactive (ir-) ET-1, big ET-1, and ET-3 in normal humans were approximately 2.0, 5.1, and 0.9 pg/ml, respectively, when corrected for recovery efficiency. In reverse-phase high-performance liquid chromatography (HPLC) analysis, immunoreactivities detected by these sandwich-EIAs were eluted at the positions of authentic ET-1, big ET-1, and ET-3, indicating that plasma levels of ET-1, big ET-1, and ET-3 were precisely measured by our methods. Levels of ir-big ET-2 and ir-big ET-3 were also detected in normal human plasma; however, further studies are needed to determine their precise values. The establishment of reliable sandwich-EIAs and the measurement of specific ETs and big ETs in normal human plasma will contribute to clarifying the biological and clinical significance of ET family peptides.
authors.affiliation: Tsukuba Research Laboratories, Takeda Chemical Industries, Ltd., Japan.
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Matsumoto
authors.forename: T
authors.initials: T
authors.lastname: Miyauchi
authors.forename: C
authors.initials: C
authors.lastname: Kitada
authors.forename: M
authors.initials: M
authors.lastname: Tsuda
authors.forename: K
authors.initials: K
authors.lastname: Goto
authors.forename: T
authors.initials: T
authors.lastname: Masaki
authors.forename: M
authors.initials: M
authors.lastname: Fujino
mesh_terms: D000328:Adult; D000918:Antibody Specificity; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D019332:Endothelin-1; D016232:Endothelins / Q000032:analysis* / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D011498:Protein Precursors / Q000032:analysis / Q000276:immunology
chemical_list: D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors