title: Circadian variation of DSIP-like material in rat plasma.
abstract: Levels of delta-sleep-inducing peptide-like immunoreactivity (DSIP-LI) in rat plasma were measured by radioimmunoassay and found to exhibit a circadian rhythm that parallelled the normal rhythm for corticosterone. The maximal plasma levels of both substances were observed to occur at about 1700h. The lowest concentrations of DSIP-LI and corticosterone were detected at 2400h and 1000h, respectively. Exposure to constant levels of illumination abolished the rhythm of DSIP-LI. It is possible that the temporal parallelism between the levels of DSIP-LI and corticosterone may represent a functional relationship between both compounds.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D003345:Corticosterone / Q000097:blood; D003624:Darkness; D003701:Delta Sleep-Inducing Peptide; D008027:Light; D008297:Male; D009842:Oligopeptides / Q000097:blood*; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats
chemical_list: D009842:Oligopeptides; D003701:Delta Sleep-Inducing Peptide; D003345:Corticosterone