title: Effect of sex hormone administration on circulating ghrelin levels in peripubertal children.
abstract: BACKGROUND
  Ghrelin levels gradually decrease throughout childhood and with advancing pubertal stage. The change during puberty is more pronounced in boys than girls.
  
  
  OBJECTIVE
  The objective of the study was to investigate whether the pubertal drop in ghrelin secretion is modified by the increase in sex hormones.
  
  
  METHODS
  Ghrelin levels were measured in 34 short peripubertal children (17 boys and 17 girls) aged 8-12.5 yr before and after sex hormone priming for GH stimulation testing.
  
  
  RESULTS
  In boys, priming with testosterone increased testosterone to pubertal levels (23.7 +/- 7.1 nmol/liter), which in turn induced a marked decrease in ghrelin (from 1615.8 +/- 418.6 to 1390.0 +/- 352.0 pg/ml) and leptin (from 8.0 +/- 4.5 to 5.8 +/- 3.2 ng/ml) and an increase in IGF-I (from 162.7 +/- 52.8 to 291.1 +/- 101.6 ng/ml) (P < 0.001 for all parameters). In girls, priming with estrogen led to a supraphysiological increase in estradiol levels (1313.8 +/- 438.0 pmol/liter), which had no effect on ghrelin, leptin, or IGF-I. There was no correlation between ghrelin levels and levels of sex hormones, leptin, or body mass index in either boys or girls.
  
  
  CONCLUSIONS
  A pharmacological increase in sex hormones is associated with a marked decline in circulating levels of ghrelin in boys but not girls. Additional longitudinal studies through puberty are needed to elucidate the physiological interaction between sex hormones and ghrelin.
authors.affiliation: Institute for Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, Petah Tiqva 49202, Israel.
authors.forename: Y
authors.initials: Y
authors.lastname: Lebenthal
authors.forename: G
authors.initials: G
authors.lastname: Gat-Yablonski
authors.forename: B
authors.initials: B
authors.lastname: Shtaif
authors.forename: A
authors.initials: A
authors.lastname: Padoa
authors.forename: M
authors.initials: M
authors.lastname: Phillip
authors.forename: L
authors.initials: L
authors.lastname: Lazar
mesh_terms: D001827:Body Height / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D002648:Child; D005080:Exercise Test; D005260:Female; D043373:Follicle Stimulating Hormone, Human / Q000097:blood; D054439:Ghrelin; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D013006:Growth Hormone / Q000494:pharmacology; D006728:Hormones / Q000097:blood; D006801:Humans; D020738:Leptin / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D036361:Peptide Hormones / Q000097:blood*; D011627:Puberty / Q000502:physiology*; D012727:Sex Characteristics
chemical_list: D043373:Follicle Stimulating Hormone, Human; D054439:Ghrelin; D012739:Gonadal Steroid Hormones; D006728:Hormones; D020738:Leptin; D036361:Peptide Hormones; D007986:Luteinizing Hormone; D013006:Growth Hormone