title: The evaluation of estradiol and leptin action on the activity of the somatotropic and gonadotropic axes in peripubertal female rats.
abstract: OBJECTIVE
  Available data suggest that estrogens and leptin play a role in the control of the pubertal process. In humans and some mammal species the increase of the activity of gonadotropic axis accompanies the decrease in the rate of growth at puberty. The effect of 17β-estradiol and/or leptin administration on the somatotropic and gonadotropic axes was studied using prepubertal female rats as an animal model.
  
  
  METHODS
  Prepubertal female rats received estradiol/saline, estradiol/leptin, oil/leptin or oil/saline (vehicles) respectively. The changes of growth rate, and serum 17β-estradiol, leptin, GH, IGF-I and gonadotropins levels as well as LHRH and estrogen receptor (ER) concentrations in the medial basal hypothalamus (MBH) and the pituitary were determined. All hormones concentrations were measured by radioimmunoassay and ER by radioligand methods .
  
  
  RESULTS
  In estradiol and/or leptin treated animals noticeable reduction of rate of growth was found. The decrease of growth in response to estradiol treatment accompanied the increase GH level and the decrease of IGF-I concentration in the circulation. Both hormones operating together activated reproductive axis, what was manifested by a significant increase of LHRH abundant in the hypothalamus as well as elevated LH and FSH levels in the circulation. In these rats a significant decrease of the estrogen receptor concentrations in the pituitary was observed.
  
  
  CONCLUSIONS
  The role of estradiol and leptin in the control of growth and reproduction seems to overlap only partially. Estradiol plays a significant role in the activation of the reproductive axis, and leptin takes part as a permissive factor in pubertal process.
authors.affiliation: Neuroendocrinology Department, Medical Centre of Postgraduate Education, Warsaw, Poland. zne@cmkp.edu.pl
authors.forename: Ewa
authors.initials: E
authors.lastname: Wolinska-Witort
authors.forename: Lidia
authors.initials: L
authors.lastname: Martynska
authors.forename: Magdalena
authors.initials: M
authors.lastname: Chmielowska
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Wasilewska-Dziubinska
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bik
authors.forename: Boguslawa
authors.initials: B
authors.lastname: Baranowska
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D004958:Estradiol / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D052681:Gonadotrophs / Q000187:drug effects / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000097:blood / Q000378:metabolism; D013006:Growth Hormone / Q000097:blood; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011960:Receptors, Estrogen / Q000378:metabolism; D012741:Sexual Maturation / Q000187:drug effects / Q000502:physiology*; D052683:Somatotrophs / Q000187:drug effects / Q000502:physiology*
chemical_list: D020738:Leptin; D011960:Receptors, Estrogen; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone