Detection of immunoreactive endothelin in plasma of hemodialysis patients.
Two types of radioimmunoassay (RIA) methods for measuring endothelin (ET) in human plasma were developed. One was an extraction procedure using a Sep-Pak C18 cartridge, the other being a direct method. By the extraction method, plasma ET levels were lower than the detectable limit (7 pg/ml) in normal subjects and elevated in hemodialysis patients. The absolute values obtained via the direct method were 20-times higher than those from extraction. Gel-filtration experiments revealed that this discrepancy was mainly due to immunoreactive (IR-) endothelin-like substances of high molecular mass near 11.6 kDa (large IR-ET). Extraction of the peptide by the C18 cartridge could eliminate interference by large IR-ET and is important in the accurate measurement of ET concentrations in plasma.
Totsune
K
K
Second Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Mouri
T
T
Takahashi
K
K
Ohneda
M
M
Sone
M
M
Saito
T
T
Yoshinaga
K
K
D000328:Adult; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D016232:Endothelins; D004730:Endothelium, Vascular; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000097:blood*; D011863:Radioimmunoassay; D006435:Renal Dialysis
D016232:Endothelins; D010455:Peptides