The influence of δ-sleep inducing peptide (DSIP) on rat pineal N-acetyltransferase (NAT) activity and melatonin levels was examined. Young adult rats received an injection of either saline or DSIP (either 15, 30 or 60 nmol/kg) at 20.00 h, immediately before lights out. DSIP at a dose of 15 nmol/kg significantly retarded the nighttime rise of pineal NAT activity and melatonin levels at 3 h into the dark phase. At the other two nocturnal time points (01.00 and 03.00 h) and the following morning (08.00 h) pineal NAT activity and melatonin levels were similar in all groups. The results confirmed a short-lived, dose-specific effect of DSIP on serotonin metabolism in the rat pineal gland. © 1986.
- Pineal gland
- δ-Sleep inducing peptide