Study summary · research use only
Delta sleep-inducing peptide (DSIP)-like material is absorbed by the gastrointestinal tract of the neonatal rat
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This study in unweaned rat pups examined whether delta sleep-inducing peptide (DSIP) enters the circulation from the gastrointestinal tract, using an analog (N-Tyr-DSIP) or radiolabeled 125I-N-Tyr-DSIP fed to pups. Plasma DSIP-like immunoreactivity significantly increased after feeding 100 micrograms/animal of N-Tyr-DSIP but not after vehicle or 1 microgram/animal, with column chromatography showing coelution with intact DSIP and des-Trp1-DSIP. A small but significant increase occurred in pups whose nursing mothers were injected with N-Tyr-DSIP but not saline. Radioactivity appeared in brain and blood of 1-2 and 10 day old pups fed 125I-N-Tyr-DSIP, and most brain radioactivity coeluted with intact peptide. The authors concluded the results indicate oral DSIP can be absorbed through the GI tract into systemic circulation.
Abstract
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.
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