Delta Sleep Inducing Peptide — a naturally occurring nonapeptide that regulates sleep architecture.
Modulates sigma receptors and gonadotropin release. Reduces somatostatin secretion (which inhibits GH release during sleep). May reduce ACTH and cortisol stress responses. Appears to promote delta wave (deep sleep) activity.
Originally isolated from rabbit brain in 1977. Naturally present in the human hypothalamus, limbic system, and pituitary. Research suggests it may improve sleep quality without the next-day sedation seen with traditional sleep aids.
The DSIP-mediated reduction in somatostatin may be why GH release during sleep is enhanced — somatostatin normally suppresses GH secretion, so reducing it during sleep allows larger nocturnal GH pulses.