title: Elevated body weight gain during the juvenile period alters neuropeptide Y-gonadotropin-releasing hormone circuitry in prepubertal heifers.
abstract: Increased body weight (BW) gain during the juvenile period leads to early maturation of the reproductive neuroendocrine system. We investigated whether a nutritional regimen that advances the onset of puberty leads to alterations in the hypothalamic neuropeptide Y (NPY) circuitry that are permissive for enhanced gonadotropin-releasing hormone (GnRH) secretion. It was hypothesized that NPY mRNA and NPY projections to GnRH and kisspeptin neurons are reduced in heifers that gain BW at an accelerated rate, compared with a lower one, during the juvenile period. Heifers were weaned at approximately 4 mo of age and fed diets to promote relatively low (0.5 kg/day; low gain [LG]) or high (1.0 kg/day; high gain [HG]) rates of BW gain until 8.5 mo of age. Heifers that gained BW at a higher rate exhibited greater circulating concentrations of leptin and reduced overall NPY expression in the arcuate nucleus. The proportion of GnRH neurons in close apposition to NPY fibers and the magnitude of NPY projections to GnRH neurons located in the mediobasal hypothalamus were reduced in HG heifers. However, no differences in NPY projections to kisspeptin neurons in the arcuate nucleus were detected between HG and LG heifers. Results indicate that a reduction in NPY innervation of GnRH neurons, particularly at the level of the mediobasal hypothalamus, occurs in response to elevated BW gain during the juvenile period. This functional plasticity may facilitate early onset of puberty in heifers.
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas.
authors.forename: Bruna R C
authors.initials: BR
authors.lastname: Alves
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas Animal Reproduction Laboratory, Texas A&M AgriLife Research, Beeville, Texas.
authors.forename: Rodolfo C
authors.initials: RC
authors.lastname: Cardoso
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas Animal Reproduction Laboratory, Texas A&M AgriLife Research, Beeville, Texas.
authors.forename: Ligia D
authors.initials: LD
authors.lastname: Prezotto
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas Animal Reproduction Laboratory, Texas A&M AgriLife Research, Beeville, Texas.
authors.forename: Jennifer F
authors.initials: JF
authors.lastname: Thorson
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas.
authors.forename: Michelle
authors.initials: M
authors.lastname: Bedenbaugh
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Sharpton
authors.affiliation: Physiologie de la Reproduction et des Comportements, INRA/CNRS/Université de Tours/Haras Nationaux, Nouzilly, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Caraty
authors.affiliation: Division of Animal Sciences, University of Missouri, Columbia, Missouri.
authors.forename: Duane H
authors.initials: DH
authors.lastname: Keisler
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas.
authors.forename: Luis O
authors.initials: LO
authors.lastname: Tedeschi
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas Animal Reproduction Laboratory, Texas A&M AgriLife Research, Beeville, Texas glwilliams@tamu.edu.
authors.forename: Gary L
authors.initials: GL
authors.lastname: Williams
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas.
authors.forename: Marcel
authors.initials: M
authors.lastname: Amstalden
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D002417:Cattle; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D059648:Kisspeptins / Q000378:metabolism; D020738:Leptin / Q000097:blood; D009474:Neurons / Q000502:physiology*; D009478:Neuropeptide Y / Q000378:metabolism*; D012741:Sexual Maturation / Q000502:physiology; D015430:Weight Gain / Q000502:physiology*
chemical_list: D059648:Kisspeptins; D020738:Leptin; D009478:Neuropeptide Y; D007987:Gonadotropin-Releasing Hormone
keywords: gonadotropin-releasing hormone; kisspeptin; leptin; neuropeptide Y; nutrition; puberty