Presence of immunoreactive salusin-alpha in human serum and urine.
Salusins, identified from a full-length enriched human cDNA library by bioinformatics analyses, show mitogenic, neuromodulatory and hemodynamic activities in rats. They are expressed in a wide variety of human tissues, but their precise structures and levels in human body fluids remain unknown. We developed a radioimmunoassay suitable for the detection of immunoreactive human salusin-alpha and characterized the molecular forms and concentrations of salusin-alpha in human serum and urine. The assay allowed for measurement of immunoreactive salusin-alpha concentrations as low as 1 fmol/tube after extraction of serum with an octyl-silica column, and the concentration required for 50% inhibition of binding was 40 fmol/tube. Cross-reactivities with salusin-beta and other bioactive peptides were negligible. Salusin-alpha-like immunoreactivity in normal human serum and urine ranged from 11.0 to 40.4 pmol/l (mean+/-S.D., 23.3+/-8.1 pmol/l, n=31) and from 18.6 to 367.3 pmol/l (mean+/-S.D., 156.8+/-95.8 pmol/l), respectively. Reverse-phase high performance liquid chromatography coupled with radioimmunoassay detection revealed a major immunoreactive component that coeluted with authentic salusin-alpha. These data indicate the presence of salusin-alpha in human serum and urine, thereby verifying the initially predicted processing sites for salusin-alpha in humans.
Sato
Kengo
K
Graduate School of Health Sciences, Tokyo Medical and Dental University, Tokyo 113-8519, Japan.
Koyama
Takatoshi
T
Tateno
Toru
T
Hirata
Yukio
Y
Shichiri
Masayoshi
M
D000328:Adult; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood* / Q000652:urine*; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay / Q000379:methods; D012680:Sensitivity and Specificity
D036341:Intercellular Signaling Peptides and Proteins; C478739:TOR2A protein, human