Delta-sleep-inducing peptide and two of its analogs reduce nocturnal increase of N-acetyltransferase activity in rat pineal gland.
Serotonin N-acetyltransferase, an enzyme of the pineal gland, converts serotonin to N-acetylserotonin. The activity of this enzyme is induced by norepinephrine in the evening to reach high levels during the dark phase. Delta-sleep-inducing peptide, a humoral sleep factor, also seems to affect circadian rhythms. Intravenous injection of this peptide or either of two of its analogs in the evening significantly reduced the increase of N-acetyltransferase 4 h later. The dose-response relationship of the peptides showed an inverted U-shaped pattern with the active dose about 30 nmol/kg. The effect appears to be dependent on the time of day of administration, as injections in the morning did not change the enzymatic activity. These findings indicate that delta-sleep-inducing peptide (and two of its analogs) can affect enzymatic activities and that these influences probably vary throughout a time period of 24 h.
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D002940:Circadian Rhythm / Q000187:drug effects*; D003701:Delta Sleep-Inducing Peptide / Q000031:analogs & derivatives; D004305:Dose-Response Relationship, Drug; D005260:Female; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D013997:Time Factors
D009842:Oligopeptides; C041971:delta-sleep-inducing peptide amine, Ala(4)-; D003701:Delta Sleep-Inducing Peptide; C033008:delta sleep-inducing peptide phosphate; D000123:Acetyltransferases; D001191:Arylamine N-Acetyltransferase