title: Characterization of the reproductive effects of the Vgf-derived peptide TLQP-21 in female rats: in vivo and in vitro studies.
abstract: BACKGROUND
  VGF (non-acronymic), a protein expressed in the hypothalamus and pituitary, is involved in the control of metabolism and body weight homeostasis. Different active peptide fragments are generated from VGF, including TLQP-21. Previous studies of our group reported that this molecule participates also in the regulation of reproductive function in male rats, with predominant stimulatory effects.
  
  
  METHODS
  We report herein a series of studies on the reproductive effects of TLQP-21 in female rats, as evaluated by a combination of in vivo and in vitro analyses.
  
  
  RESULTS
  TLQP-21 modestly increased serum LH levels after systemic administration and directly stimulated pituitary LH and FSH secretion in prepubertal female rats, while acute central injection of TLQP-21 was unable to modify LH secretion at this age. Repeated central administration of TLQP-21 during the pubertal transition (between PND-28 and -35) to female rats fed ad libitum advanced the timing of vaginal opening and increased the percentage of animals with signs of ovulation. Moreover, an analogous treatment slightly enhanced ovarian maturation in pubertal female rats subjected to chronic undernutrition, but was unable to rescue the delay of vaginal opening induced by food deprivation. In addition, TLQP-21 oppositely modified LH secretion in adult female rats depending on the stage of the ovarian cycle: it stimulated LH secretion when injected in the morning of diestrus and decreased the magnitude of the preovulatory LH (but not FSH) surge when injected in the afternoon of proestrus.
  
  
  CONCLUSIONS
  Our data are the first to document the potential involvement of TLQP-21 in the control of reproductive function in female rats.
authors.affiliation: Department of Cell Biology, Physiology and Immunology, Faculty of Medicine, University of Córdoba, CIBER Fisiopatología de la Obesidad y Nutrición, and Instituto Maimónides de Investigaciones Biomédicas-IMIBIC/Hospital Reina Sofía, Córdoba, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Aguilar
authors.forename: Rafael
authors.initials: R
authors.lastname: Pineda
authors.forename: Francisco
authors.initials: F
authors.lastname: Gaytán
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Sánchez-Garrido
authors.forename: Magdalena
authors.initials: M
authors.lastname: Romero
authors.forename: Antonio
authors.initials: A
authors.lastname: Romero-Ruiz
authors.forename: Francisco
authors.initials: F
authors.lastname: Ruiz-Pino
authors.forename: Manuel
authors.initials: M
authors.lastname: Tena-Sempere
authors.forename: Leonor
authors.initials: L
authors.lastname: Pinilla
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006706:Homeostasis / Q000502:physiology; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008845:Microinjections; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000008:administration & dosage* / Q000235:genetics; D010446:Peptide Fragments / Q000008:administration & dosage* / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D012098:Reproduction / Q000187:drug effects* / Q000502:physiology; D012727:Sex Characteristics; D016896:Treatment Outcome
chemical_list: D009479:Neuropeptides; D010446:Peptide Fragments; C522412:TLQP-21 peptide; C062040:Vgf protein, rat; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone