Melatonin synthesis: analysis of the more than 150-fold nocturnal increase in serotonin N-acetyltransferase messenger ribonucleic acid in the rat pineal gland

Endocrinology. 1996 Jul;137(7):3033-45. doi: 10.1210/endo.137.7.8770929.


In vertebrates, the circadian rhythm in the activity of serotonin N-acetyltransferase [arylalkylamine N-acetyltransferase (AA-NAT); EC] drives the daily rhythm in circulating melatonin. We have discovered that expression of the AA-NAT gene in the rat pineal gland is essentially turned off during the day and turned on at night, resulting in a more than 150-fold rhythm. Expression is regulated by a photoneural system that acts through an adrenergic-cAMP mechanism in pinealocytes, probably involving cAMP response element-binding protein phosphorylation. Turning off AA-NAT expression appears to involve de novo synthesis of a protein that attenuates transcription. A approximately 10-fold night/day rhythm in AA-NAT messenger RNA occurs in the retina, and AA-NAT messenger RNA is also detected at low levels in the brain.

MeSH terms

  • Adrenergic beta-Agonists / pharmacology
  • Adrenergic beta-Antagonists / pharmacology
  • Amino Acid Sequence
  • Animals
  • Arylamine N-Acetyltransferase / biosynthesis*
  • Arylamine N-Acetyltransferase / chemistry
  • Brain / enzymology*
  • Circadian Rhythm*
  • Consensus Sequence
  • DNA, Complementary
  • Darkness
  • Light
  • Male
  • Melatonin / biosynthesis*
  • Molecular Sequence Data
  • Organ Specificity
  • Phenylephrine / pharmacology
  • Pineal Gland / enzymology*
  • Pineal Gland / physiology
  • Polymerase Chain Reaction
  • Propranolol / pharmacology
  • RNA, Messenger / analysis
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, beta / physiology
  • Sequence Homology, Amino Acid
  • Sheep
  • Transcription, Genetic*


  • Adrenergic beta-Agonists
  • Adrenergic beta-Antagonists
  • DNA, Complementary
  • RNA, Messenger
  • Receptors, Adrenergic, beta
  • Phenylephrine
  • Propranolol
  • Arylamine N-Acetyltransferase
  • Melatonin

Associated data

  • GENBANK/U29663
  • GENBANK/U38306
  • GENBANK/U77455