title: Differential levels of "urotensin-II-like" activity determined by radio-receptor and radioimmuno-assays.
abstract: Plasma and urinary levels of "urotensin(U)-II-like" substances determined in healthy human volunteers were 12.4 +/- 0.6 ng/ml and 2.2 +/- 0.3 ng/ml by RIA, an order of magnitude lower than that seen by RRA, 167.5 +/- 9.5 ng/ml and 65.2 +/- 4.3 ng/ml. HPLC demonstrated the existence of at least three prominent activity peaks in plasma and urine, the more hydrophobic of which did not co-elute with U-II, degradation products or URP. RRA and RIA recognized these peaks with contrasting efficacy. As such, published levels of "U-II-like" activity should be interpreted with caution until a better understanding is obtained regarding what species specific RIA and RRA assay reagents interact with.
authors.affiliation: Department of Vascular Biology and Thrombosis (UW2510), Cardiovascular and Urogenital Center of Excellence for Drug Discovery (CEDD), GlaxoSmithKline, P.O. Box 1539, 709 Swedeland Road, King of Prussia, PA 19406-0939, USA. nambi_aiyar-1@gsk.com
authors.forename: Nambi
authors.initials: N
authors.lastname: Aiyar
authors.forename: Brian
authors.initials: B
authors.lastname: Guida
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Ao
authors.forename: Jyoti
authors.initials: J
authors.lastname: Disa
authors.forename: Diane
authors.initials: D
authors.lastname: Naselsky
authors.forename: David J
authors.initials: DJ
authors.lastname: Behm
authors.forename: Jui-Lan
authors.initials: JL
authors.lastname: Su
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Kull
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Douglas
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay / Q000379:methods; D011869:Radioligand Assay / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D014579:Urotensins / Q000032:analysis / Q000097:blood / Q000652:urine
chemical_list: D014579:Urotensins; C029677:urotensin II