DSIP (Delta Sleep-Inducing Peptide)

DSIP (Delta Sleep-Inducing Peptide) is an endogenous nonapeptide (sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, MW ~848 Da) first isolated from rabbit cerebral venous blood by Schoenenberger and Monnier in 1977 at the University of Basel. It is found naturally in the human hypothalamus, pituitary, and peripheral organs, with plasma concentrations showing a circadian rhythm that peaks at night. Its full receptor pharmacology remains under investigation.

Lyophilized DSIP is stored at -20C and is stable for extended periods. Reconstituted with bacteriostatic water, it is refrigerated at 2-8C and used within a few weeks. The peptide is sensitive to oxidation at the tryptophan residue, so it is protected from light and used promptly after reconstitution.