title: Possible effects of melatonin on thymus gland after pinealectomy in rats.
abstract: OBJECTIVE
  The purpose of this study was to investigate the effects of pinealectomy and pinealectomy plus melatonin administration on thymus weight and histology in adult Wistar-albino rats.
  
  
  METHODS
  The animals were divided into three groups. Group I and Group II were designated as control (sham-pinealectomized) and pinealectomized rats, respectively. They received 10% ethanol (0.1 ml per day s.c.) alone. The rats in Group III were pinealectomized and daily injected with melatonin (3 mg/kg/0.1 ml 10% ethanol per day s.c.) commencing on the day seven after surgical operation. Injections were applied for two months.
  
  
  RESULTS
  The thymus atrophied and its weight decreased after pinealectomy (p<0.001). The cortico-medullary boundary could not be distinguished and in the thymus induced a loss of lymphoid elements, increased number of phagocytic macrophages and enlarged blood vessels. Melatonin prevented the thymic involution.
  
  
  CONCLUSIONS
  These results suggest that pinealectomy decreases thymus weight and that long-term administration of melatonin restores thymus weight to normal levels.
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, Akdeniz University, Burdur, Turkey. honer@altavista.net
authors.forename: Hakan
authors.initials: H
authors.lastname: Oner
authors.forename: Ilter
authors.initials: I
authors.lastname: Kus
authors.forename: Jale
authors.initials: J
authors.lastname: Oner
authors.forename: Murat
authors.initials: M
authors.lastname: Ogetürk
authors.forename: Enver
authors.initials: E
authors.lastname: Ozan
authors.forename: Ahmet
authors.initials: A
authors.lastname: Ayar
mesh_terms: D000818:Animals; D001284:Atrophy / Q000517:prevention & control; D008297:Male; D008550:Melatonin / Q000502:physiology*; D009929:Organ Size; D010870:Pineal Gland / Q000502:physiology* / Q000601:surgery; D051381:Rats; D017208:Rats, Wistar; D013950:Thymus Gland / Q000473:pathology* / Q000502:physiology*
chemical_list: D008550:Melatonin