Melatonin entrainment of the circadian N-acetyltransferase rhythm in the newborn rat pineal gland

• Published in: Journal of pineal research 1997-10, Vol.23 (3), p.136-141
• Main Authors: TRAVNICKOVA, Z, ILINEROVA, H
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Antioxidants - administration & dosage; Antioxidants - pharmacology; Arylamine N-Acetyltransferase - metabolism; Biological and medical sciences; circadian; Circadian Rhythm - drug effects; entrainment; Female; Fundamental and applied biological sciences. Psychology; Hormones and neuropeptides. Regulation; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Injections, Subcutaneous; melatonin; Melatonin - administration & dosage; Melatonin - pharmacology; newborn rat; pineal gland; Pineal Gland - enzymology; Pregnancy; Rats; Rats, Wistar; Vertebrates: endocrinology
• ISSN: 0742-3098; 1600-079X
• DOI: 10.1111/j.1600-079X.1997.tb00346.x

Trávníčková Z, Illnerová H. Melatonin entrainment of the circadian N‐acetyltransferase rhythm in the newborn rat pineal gland. J. Pineal Res. 1997; 23:136–141. © Munksgaard, Copenhagen In 15‐day‐old control and vehicle‐treated rats, the evening rise of the pineal N‐acetyltransferase occurred at the same time as in their mothers, whereas in 5‐day‐old pups, the rise occurred by 2–3 hr earlier. Four‐day administration of melatonin in the late day phase advanced the N‐acetyltransferase rise in 15‐day‐old rats as compared with the rise in the vehicle‐treated animals; a slight melatonin induced phase advance in 5‐ and 27‐day‐old rats was not significant. The data indicate that the newborn rat's circadian pacemaker controlling the rhythmic N‐acetyltransferase rise may be entrained by exogenous melatonin. It appears, however, that the maternal melatonin transferred via milk cannot entrain the pup's pacemaker by phase advancing it, since the N‐acetyltransferase rise in the pups begins earlier or at the same time as maternal melatonin production driven by the N‐acetyltransferase rhythm.