Delta-Sleep-Inducing Peptide (DSIP) Inhibited CRF-Induced ACTH Secretion from Rat Anterior Pituitary Gland In Vitro

Summary

Delta-sleep-inducing peptide (DSIP, 10^-9-10^-7M) significantly inhibited the CRF-induced ACTH release from rat anterior pituitary quarters in vitro. 10^-8M DSIP showed the most prominent inhibition. DSIP (10^-8M) also inhibited the CRF-activated cAMP levels in anterior pituitary tissue. DSIP did not influence basal ACTH or cAMP levels. Prostaglandin E₂ (PGE₂)-release from anterior pituitary quarters was not changed by DSIP. From these results, we conclude that DSIP inhibits CRF-induced ACTH release at the pituitary level through the inhibition of the cAMP system in corticotrophs. The involvement of PGE₂ in this phenomenon is unlikely.