Delta-sleep-inducing peptide (DSIP) is a neuropeptide with amino acid sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu and molecular mass 848.81 g/mol. DSIP occurs in both free and bound forms in the hypothalamus, limbic system and pituitary as well as various peripheral organs, tissues and body fluids. In the pituitary it co-localises with many peptide and non-peptide mediators such as corticotropin-like intermediate peptide (CLIP), adrenocorticotrophic hormone (ACTH), melanocyte-stimulating hormone (MSH), thyroid-stimulating hormone (TSH) and melanin concentrating hormone (MCH). Delta-sleep-inducing peptide is abundant in the gut secretory cells and in the pancreas where it co-localises with glucagon.
