title: Serotoninergic and melatoninergic systems are expressed in mouse embryonic fibroblasts NIH3T3 cells.
abstract: OBJECTIVE
  Melatonin not only plays an important role in regulating circadian rhythms, but is also involved in antioxidative defense and immunomodulation. Circulating melatonin levels are derived primarily from the pineal gland while other sources of melatonin have also been reported. Recently, we reported that cultured rat cortical astrocytes and glioma C6 cells synthesize melatonin. In addition, apolipoprotein E genotype influences melatonin biosynthesis by regulating NAT and MAOA expression in C6 cells.
  
  
  METHODS
  Here, we investigated the expression of genes and enzymes that is responsible for the multistep conversion of tryptophan to serotonin and further to melatonin in mouse embryonic fibroblasts NIH3T3 cells by radioimmunoassay, Immunofluorescence staining, real-time PCR and Western blotting techniques.
  
  
  RESULTS
  Our results showed that cultured NIH3T3 cells could synthesize melatonin and serotonin. Serotonin N-acetyltransferase (NAT), the key enzyme in the pathway of melatonin synthesis, was also detectable using both by western blot and PCR methods. In addition, two other key enzymes, tryptophan hydroxylase (TPH1 and TPH2) for serotonin synthesis and the metabolic enzyme monoamine oxidase A (MAOA) for 5-HT, were present in NIH3T3 cell line.
  
  
  CONCLUSIONS
  In conclusion, we provided evidence that the NIH3T3 cells can synthesize intrinsic serotonin and melatonin and express key enzymes related biosynthetic pathways.
authors.affiliation: University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Ya-Jing
authors.initials: YJ
authors.lastname: Liu
authors.forename: Fan-Tao
authors.initials: FT
authors.lastname: Meng
authors.forename: Lei
authors.initials: L
authors.lastname: Wu
authors.forename: Jiang-Ning
authors.initials: JN
authors.lastname: Zhou
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics; D001253:Astrocytes / Q000166:cytology / Q000502:physiology*; D001932:Brain Neoplasms; D045744:Cell Line, Tumor; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D015870:Gene Expression / Q000502:physiology; D005838:Genotype; D005910:Glioma; D008550:Melatonin / Q000096:biosynthesis / Q000502:physiology*; D051379:Mice; D008995:Monoamine Oxidase / Q000235:genetics / Q000378:metabolism; D041681:NIH 3T3 Cells; D051381:Rats; D012701:Serotonin / Q000096:biosynthesis / Q000502:physiology*; D014365:Tryptophan Hydroxylase / Q000235:genetics / Q000378:metabolism
chemical_list: D001057:Apolipoproteins E; D012701:Serotonin; C487801:Tph1 protein, mouse; C487802:Tph2 protein, mouse; D014365:Tryptophan Hydroxylase; C504570:tph1 protein, rat; C504569:tph2 protein, rat; D008995:Monoamine Oxidase; D008550:Melatonin