title: High plasma triglyceride levels strongly correlate with low kisspeptin in the arcuate nucleus of male rats.
abstract: OBJECTIVE
  It is well known that reproductive capacity is lower in obese individuals, but what mediators and signals are involved is unclear. Kisspeptin is a potent stimulator of GnRH release, and it has been suggested that kisspeptin neurons located in the arcuate nucleus transmit metabolic signals to the GnRH neurons.
  
  
  METHODS
  In this study, we measured body weight and plasma concentrations of leptin, insulin, testosterone, and triglycerides after high fat diet exposure and correlated these parameters with the number of kisspeptin-immunoreactive neurons in the arcuate nucleus of male rats. In this model, a high fat diet (45% or 60% energy from fat, respectively) or a control diet (10% energy from fat) was provided after weaning for three months.
  
  
  RESULTS
  We find a significant increase in body weight and plasma leptin concentration, but no change in the number of kisspeptin-immunoreactive cells with increased fat in the diet. Kisspeptin-immunoreactive cells are not correlated with body weight, testosterone, leptin or insulin. However, we find that the number of kisspeptin-immunoreactive cells is strongly and negatively correlated with the level of plasma triglycerides (R2=0.49, p=0.004).
  
  
  CONCLUSIONS
  We find a strong negative correlation between plasma triglyceride concentrations and the number of kisspeptin neurons in the rat arcuate nucleus regardless of the percentage of fat in the diet. In line with the lipotoxicity hypothesis, our results suggest that it is the level of hypertriglyceridemia per se that is a detrimental factor for kisspeptin expression in the arcuate nucleus.
authors.forename: A
authors.initials: A
authors.lastname: Overgaard
authors.forename: A M
authors.initials: AM
authors.lastname: Axel
authors.forename: M E
authors.initials: ME
authors.lastname: Lie
authors.forename: H H
authors.initials: HH
authors.lastname: Hansen
authors.forename: J D
authors.initials: JD
authors.lastname: Mikkelsen
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood; D059305:Diet, High-Fat; D007328:Insulin / Q000097:blood; D059648:Kisspeptins / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013739:Testosterone / Q000097:blood; D014280:Triglycerides / Q000097:blood*
chemical_list: D015415:Biomarkers; D007328:Insulin; D059648:Kisspeptins; D014280:Triglycerides; D013739:Testosterone
keywords: high fat diet; kisspeptin; lipotoxicity.; obesity; triglycerides