title: The expression of Per1 and Aa-nat genes in the pineal gland of postnatal rats.
abstract: BACKGROUND
  The circadian rhythm of melatonin synthesis is controlled by the master clock, suprachiasmatic nucleus (SCN). The level of melatonin changes throughout the aging process. The SCN's rhythm is driven by autoregulatory feedback loop composed of a set of clock genes families and their corresponding proteins. The Period (Per1), one of clock gene develops gradually during postnatal ontogenesis in the rat SCN and is also expressed in the pineal gland.
  
  
  OBJECTIVE
  It is of interest to study the relationship between the postnatal development of Per1 and Aa-nat, genes that produce the rate-limiting enzyme in melatonin synthesis, in the pineal.
  
  
  METHODS
  Daily profiles of mRNA expression of Per1 and Aa-nat were analyzed in the pineal gland of pups at postnatal ages 4 (P4), P8, P16 and P32, at puberty age of 6 weeks; and in 8 week-old adult rats by real-time PCR.
  
  
  RESULTS
  As early as P4, Per1 and Aa-nat mRNAs were expressed and existed at relatively high levels during the nighttime. They gradually increased until puberty and decreased at 8 weeks of age. Additionally, the nocturnal changes of Per1 and Aa-nat mRNA levels in the rat pineal gland from P4 to adults were strongly correlated at r = 0.97 (p < 0.01).
  
  
  CONCLUSIONS
  The present data indicate that there is a close relationship between the expression pattern of Per1 and that of melatonin synthesis during the development of postnatal rats.
authors.affiliation: Department of Anatomy, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand.
authors.forename: Prapimpun
authors.initials: P
authors.lastname: Wongchitrat
authors.forename: Piyarat
authors.initials: P
authors.lastname: Govitrapong
authors.forename: Pansiri
authors.initials: P
authors.lastname: Phansuwan-Pujito
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D047068:Arylalkylamine N-Acetyltransferase / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics; D015870:Gene Expression; D008550:Melatonin / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D056950:Period Circadian Proteins / Q000235:genetics; D010870:Pineal Gland / Q000201:enzymology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D013493:Suprachiasmatic Nucleus / Q000378:metabolism
chemical_list: C443439:Gprasp1 protein, rat; D009419:Nerve Tissue Proteins; D056950:Period Circadian Proteins; D012333:RNA, Messenger; D047068:Arylalkylamine N-Acetyltransferase; D008550:Melatonin