Radioimmunoassay of DSIP-like material in human blood: possible protein binding.
A radioimmunoassay (RIA) for DSIP-like material was established in unextracted human plasma. Most of the immunoreactivity was found in a "large" fraction while a much smaller amount co-eluted with DSIP from Sephadex as a "free" fraction. Both peaks progressively increased with increasing amounts of added DSIP. Acidification, but not treatment with charcoal-dextran, resulted in a relative decrease in the "large" peak and an increase in the "free" peak. This RIA, therefore, appears to measure both bound and free forms of DSIP-like immunoreactivity, the levels of which were higher at 4 p.m. than at 8 a.m.
D000818:Animals; D002940:Circadian Rhythm; D003701:Delta Sleep-Inducing Peptide; D004285:Dogs; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051379:Mice; D009842:Oligopeptides / Q000097:blood*; D011485:Protein Binding; D011863:Radioimmunoassay
D009842:Oligopeptides; D003701:Delta Sleep-Inducing Peptide