title: Insulins, leptin and feeding in a population of Peromyscus leucopus (white-footed mouse) with variable fertility.
abstract: This article is part of a Special Issue "Energy Balance". Natural populations display a variety of reproductive responses to environmental cues, but the underlying physiology that causes these responses is largely unknown. This study tested the hypothesis that heritable variation in reproductive traits can be described by heritable variation in concentrations of hormones critical to both energy balance and reproduction. To test this hypothesis, we used mouse lines derived from a wild population and selectively bred for response to short day photoperiod. Reproductive and metabolic traits of Peromyscus leucopus display heritable variation when held in short photoperiods typical of winter. Our two lines of mice have phenotypes spanning the full range of variation observed in nature in winter. We tested male and female mice for heritable variation in fasted serum concentrations of three hormones involved in energetic regulation: leptin, insulin-like growth factor 1 (IGF-1) and insulin, as well as the effects of exogenous leptin and a high energy diet on reproductive maturation. Exogenous leptin decreased food intake, but protected males from the reduction in testis mass caused by equivalent food restriction in pair-fed, saline-infused controls. A high energy diet resulted in calorie adjustment by the mice, and failed to alter reproductive phenotype. Concentrations of the three hormones did not differ significantly between selection lines but had correlations with measures of food intake, fertility, blood glucose, and/or body mass. There was evidence of interactions between reproductive traits and hormones related to energy balance and reproduction, but this study did not find evidence that variation in these hormones caused variation in reproductive phenotype.
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA; Department of Biology, Johns Hopkins University, Baltimore, MD, USA. Electronic address: jtwhite@email.wm.edu.
authors.forename: Jordan T
authors.initials: JT
authors.lastname: White
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: desantoc@wusm.wustl.edu.
authors.forename: Cori L
authors.initials: CL
authors.lastname: DeSanto
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: connie.gibbons@gmail.com.
authors.forename: Connie
authors.initials: C
authors.lastname: Gibbons
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: cklardner@email.wm.edu.
authors.forename: Casey K
authors.initials: CK
authors.lastname: Lardner
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: andrew.panakos@gmail.com.
authors.forename: Andrew
authors.initials: A
authors.lastname: Panakos
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: sr5z@virginia.edu.
authors.forename: Salehin
authors.initials: S
authors.lastname: Rais
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: kathy_r_sharp@yahoo.com.
authors.forename: Kathy
authors.initials: K
authors.lastname: Sharp
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: Shannon.D.Sullivan@Medstar.net.
authors.forename: Shannon D
authors.initials: SD
authors.lastname: Sullivan
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: wtidhar@yahoo.co.uk.
authors.forename: Wendy
authors.initials: W
authors.lastname: Tidhar
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: Lmpina@gmail.com.
authors.forename: Leanne
authors.initials: L
authors.lastname: Wright
authors.affiliation: Applied Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, MD 20892, USA. Electronic address: berrigad@mail.nih.gov.
authors.forename: David
authors.initials: D
authors.lastname: Berrigan
authors.affiliation: Department of Biology, College of William and Mary, Williamsburg, VA, USA. Electronic address: pdheid@wm.edu.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Heideman
mesh_terms: D000818:Animals; D004435:Eating / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005298:Fertility / Q000502:physiology; D007328:Insulin / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000097:blood* / Q000494:pharmacology; D008297:Male; D010542:Peromyscus / Q000502:physiology*; D010641:Phenotype; D017440:Photoperiod; D012098:Reproduction / Q000502:physiology*
chemical_list: D007328:Insulin; D020738:Leptin; D007334:Insulin-Like Growth Factor I
keywords: Calorie adjustment; Energetics; Food intake; Genetic variation; Insulin; Insulin-like growth factor 1; Leptin; Natural population; Photoperiod; Reproduction