title: Increased litter size and suckling intensity inhibit KiSS-1 mRNA expression in rat arcuate nucleus.
abstract: OBJECTIVE
  The effect of litter size and suckling intensity on the expression of KiSS-1 mRNA in the arcuate nucleus (ARC) of rats were evaluated.
  
  
  METHODS
  Thirty two pregnant and four non-lactating ovariectomized (as control group) rats were used in this experiment. Lactating rats were allotted to eight equal groups. In three groups, litter size was adjusted to 5, 10, or 15 pups upon parturition and allowed to suckle their pups continuously by 8 days postpartum. In the other three groups, litter size was adjusted to five upon birth; the pups were separated from the dams for 6 hr on day 8 postpartum, after which the pups were allowed to suckle their dams for 2.5, 5, or 7.5 min prior to killing the dams. Two groups of lactating rats with either 10 or 15 pups were separated from their pups for 6 hr on day 8 postpartum, after which the pups were allowed to suckle their dams for 5 min before the dams were killed on day 8 postpartum. The ARC was removed and the expression of KiSS-1 mRNA was evaluated, using real-time PCR.
  
  
  RESULTS
  The expression of KiSS-1 mRNA in the ARC was decreased as the litter size and intensity of suckling stimulus were increased. The effect of suckling intensity on the expression of KiSS-1 mRNA was more pronounced than that of litter size.
  
  
  CONCLUSIONS
  Increased litter size and suckling intensity decreased KiSS-1 mRNA expression in the ARC which may contribute to lactation anestrus in rat.
authors.affiliation: Department of Animal Sciences, College of Agriculture, Shiraz University, Shiraz, Iran.
authors.forename: Atefeh
authors.initials: A
authors.lastname: Noroozi
authors.affiliation: Department of Animal Sciences, College of Agriculture, Shiraz University, Shiraz, Iran.
authors.forename: Mohammad Reza Jafarzadeh
authors.initials: MR
authors.lastname: Shirazi
authors.affiliation: Department of Animal Sciences, College of Agriculture, Shiraz University, Shiraz, Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Zamiri
authors.affiliation: Infertility Research Center, Shiraz University of Medical Sciences, Shiraz, Iran ; Transgenic Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Amin
authors.initials: A
authors.lastname: Tamadon
authors.affiliation: Department of Animal Sciences, College of Agriculture, Shiraz University, Shiraz, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Akhlaghi
authors.affiliation: Transgenic Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran ; Department of Pharmacology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Nader
authors.initials: N
authors.lastname: Tanideh
authors.affiliation: Biotechnology Institute, College of Agriculture, Shiraz University, Shiraz, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Niazi
authors.affiliation: Biotechnology Institute, College of Agriculture, Shiraz University, Shiraz, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Moghadam
keywords: Arcuate nucleus; KiSS-1 mRNA; Lactating rat; Litter size; Suckling intensity