Delta sleep-inducing peptide (DSIP)-like material is absorbed by the gastrointestinal tract of the neonatal rat.
Entry of delta sleep-inducing peptide (DSIP) into the circulation from the gastrointestinal (GI) tract was studied in unweaned rat pups. The pups were fed an analog of DSIP (N-Tyr-DSIP) or 125I-N-Tyr-DSIP and blood samples collected. Significant increases in plasma DSIP-like immunoreactivity occurred after the feeding of 100 micrograms/animal of N-Tyr-DSIP but not after vehicle (normal saline) or 1 microgram/animal. Column chromatography showed this immunoreactivity to coelute with intact DSIP and des-Trp1-DSIP. A small but statistically significant increase of immunoreactivity occurred in the plasma of pups whose nursing mothers were injected with N-Tyr-DSIP but not in those whose mothers were injected with saline. Radioactivity appeared in both the brain and blood of 1-2 and 10 day old rat pups fed 125I-N-Tyr-DSIP. Although only a small amount of the radioactivity in plasma co-eluted with intact 125I-N-Tyr-DSIP on column chromatography, almost all of the radioactivity in brain did, suggesting that the radioactivity in the brain represented crossing of the blood-brain-barrier by the peptide and not just contamination by blood. The results cannot be explained by either regurgitation of intestinal contents, or by stimulation of endogenous peptide. They show that a DSIP peptide administered orally can be absorbed through the GI tract into the systemic circulation.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D002845:Chromatography; D003701:Delta Sleep-Inducing Peptide / Q000031:analogs & derivatives; D004064:Digestive System / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D007774:Lactation; D009842:Oligopeptides / Q000097:blood / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains
D009842:Oligopeptides; C039556:delta sleep-inducing peptide, N-Tyr-; D003701:Delta Sleep-Inducing Peptide