title: Inhibition of RNA synthesis differentially affects in vitro melatonin release from the pineal organs of ayu (Plecoglossus altivelis) and rainbow trout (Oncorhynchus mykiss).
abstract: The effects of actinomycin D (RNA synthesis inhibitor) and cycloheximide (protein synthesis inhibitor) on melatonin release from the cultured pineal organ of two teleosts with or without the circadian regulation of melatonin production (ayu Plecoglossus altivelis and rainbow trout Oncorynchus mykiss, respectively) were investigated. Actinomycin D decreased melatonin release from the pineal organ during the dark phase but there was a significant difference between the two species (22.2% for ayu and 59.1% for trout as compared with the respective control). This difference might be due to whether the circadian regulation via gene transcription of melatonin synthesis exists or not. On the other hand, cycloheximide decreased melatonin release to approximately 1% in both species, indicating that the fish pineal organ requires de novo protein synthesis to maintain rhythmic melatonin release.
authors.affiliation: Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, 113-8657, Tokyo, Japan. mizusawa@marine.fs.a.u-tokyo.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Mizusawa
authors.forename: M
authors.initials: M
authors.lastname: Iigo
authors.forename: T
authors.initials: T
authors.lastname: Masuda
authors.forename: K
authors.initials: K
authors.lastname: Aida
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects* / Q000502:physiology; D003513:Cycloheximide / Q000494:pharmacology; D003545:Cysteine / Q000493:pharmacokinetics; D003609:Dactinomycin / Q000494:pharmacology; D008550:Melatonin / Q000096:biosynthesis / Q000378:metabolism*; D008715:Methionine / Q000493:pharmacokinetics; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000187:drug effects; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D017686:Oncorhynchus mykiss / Q000033:anatomy & histology / Q000378:metabolism*; D009924:Organ Culture Techniques; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012313:RNA / Q000096:biosynthesis* / Q000187:drug effects; D014316:Tritium / Q000493:pharmacokinetics; D014529:Uridine / Q000493:pharmacokinetics
chemical_list: D009419:Nerve Tissue Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D014316:Tritium; D003609:Dactinomycin; D012313:RNA; D003513:Cycloheximide; D008715:Methionine; D008550:Melatonin; D003545:Cysteine; D014529:Uridine