title: Genetics of leptin expression in baboons.
abstract: OBJECTIVE
  Leptin gene expression is higher in females than in males, and is regulated by many factors including energy intake and insulin, but little is known about the inheritance of leptin gene expression. We have investigated leptin (LEP) gene express-ion, to determine whether it is heritable, and whether the difference in LEP expression between males and females has a genetic component.
  
  
  METHODS
  A total of 319 baboons (Papio hamadryas) (220 females, 99 males) from a captive, pedigreed colony.
  
  
  METHODS
  We cloned a baboon LEP cDNA, and quantified LEP mRNA expression in baboon omental adipose tissue using a ribonuclease protection assay. In addition, we assayed circulating leptin levels, adipocyte cell volume, and weight. We used maximum likelihood-based variance decomposition methods to determine the genetic architecture of LEP levels, including testing for genotype-by-sex interaction.
  
  
  RESULTS
  Omental LEP mRNA expression was significantly and positively correlated with weight and adipocyte cell volume in baboons. Both mRNA and plasma levels of leptin were higher in females than in males, and both measures were heritable. The results of our genetic analysis show that there was a genotype-by-sex interaction in the levels of plasma leptin, but not in omental LEP mRNA.
  
  
  CONCLUSIONS
  As in humans, baboon leptin mRNA and protein levels are expressed at a higher level in females than in males. We detected evidence that the plasma levels were affected by genes that are differentially expressed in males and females, while the omental mRNA levels were not. This finding suggests that the genes that differentially regulate plasma leptin levels between males and females may exert their effects on post-transcriptional processes.
authors.affiliation: Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, TX, USA. scole@darwin.sfbr.org
authors.forename: S A
authors.initials: SA
authors.lastname: Cole
authors.forename: L J
authors.initials: LJ
authors.lastname: Martin
authors.forename: K W
authors.initials: KW
authors.lastname: Peebles
authors.forename: M M
authors.initials: MM
authors.lastname: Leland
authors.forename: K
authors.initials: K
authors.lastname: Rice
authors.forename: J L
authors.initials: JL
authors.lastname: VandeBerg
authors.forename: J
authors.initials: J
authors.lastname: Blangero
authors.forename: A G
authors.initials: AG
authors.lastname: Comuzzie
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D005786:Gene Expression Regulation; D020738:Leptin / Q000097:blood / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009765:Obesity / Q000235:genetics; D010215:Papio / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D012737:Sex Factors
chemical_list: D020738:Leptin; D012333:RNA, Messenger