title: Growth hormone and prolactin response to ghrelin during the normal menstrual cycle.
abstract: OBJECTIVE
  It has been suggested that exogenous oestradiol augments ghrelin-induced growth hormone (GH) secretion in postmenopausal women. Whether endogenous oestrogens exert a similar effect during the normal menstrual cycle is not known. The aim of this study was to test the hypothesis that physiological changes in ovarian steroids during the normal menstrual cycle modulate GH and prolactin (PRL) response to ghrelin.
  
  
  METHODS
  Healthy women were studied in three phases of the normal menstrual cycle.
  
  
  METHODS
  Ten healthy normally cycling women.
  
  
  METHODS
  A single dose of ghrelin (1 microg/kg) was administered intravenously in the early and late follicular phases and in the mid-luteal phase of the cycle. Saline was injected in the preceding cycle. Blood samples were taken before ghrelin or saline injection (time 0) and also at -15, 15, 30, 45, 60, 75, 90 and 120 min. The GH and PRL responses were assessed.
  
  
  RESULTS
  Serum oestradiol and progesterone concentrations showed the variations of a normal menstrual cycle. After ghrelin administration, in the three phases of the cycle, plasma ghrelin and serum GH and PRL levels increased rapidly, peaking at 30 min and declining gradually thereafter (P < 0.001). There were no significant differences in the hormone levels between the three phases at all time points. No changes in GH and PRL levels were seen after saline injection.
  
  
  CONCLUSIONS
  These results demonstrate that GH and PRL responses to ghrelin do not change across the menstrual cycle. It is suggested that the action of ghrelin on the pituitary somatotrophs is modulated differentially by endogenous and exogenous ovarian steroids.
authors.affiliation: Department of Obstetrics and Gynaecology, Medical School, University of Thessalia, Larissa, Greece.
authors.forename: Christina I
authors.initials: CI
authors.lastname: Messini
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Dafopoulos
authors.forename: Nektarios
authors.initials: N
authors.lastname: Chalvatzas
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Georgoulias
authors.forename: Ioannis E
authors.initials: IE
authors.lastname: Messinis
mesh_terms: D000328:Adult; D005260:Female; D054439:Ghrelin / Q000008:administration & dosage* / Q000097:blood; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D008597:Menstrual Cycle / Q000097:blood / Q000187:drug effects*; D011388:Prolactin / Q000097:blood*; D055815:Young Adult
chemical_list: D054439:Ghrelin; D011388:Prolactin; D013006:Growth Hormone