Sexual dimorphism in the maturation of the pituitary-gonadal axis, assessed by GnRH agonist challenge

Citation
N. Potau et al., Sexual dimorphism in the maturation of the pituitary-gonadal axis, assessed by GnRH agonist challenge, EUR J ENDOC, 141(1), 1999, pp. 27-34
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
EUROPEAN JOURNAL OF ENDOCRINOLOGY
ISSN journal
0804-4643 → ACNP
Volume
141
Issue
1
Year of publication
1999
Pages
27 - 34
Database
ISI
SICI code
0804-4643(199907)141:1<27:SDITMO>2.0.ZU;2-M
Abstract
Objective: To assess whether the maturational changes of the pituitary-gona dal axis in a healthy population show gender-specific changes and to establ ish normative data for the different Tanner stages. Design: Prospective, cross-sectional study. Methods: The GnRH agonist leuprolide acetate (500 mu g) was administered s. c, to 60 boys and 81 girls (age range, 5-17 years), Serum steroids and gona dotropins were determined at 0 and 24 h and at 0, 3 and 24 h after GnRH ago nist challenge respectively, whereas IGF-I, IGF-binding protein-1 (IGFEP-1) , IGFBP-3 and sex hormone-binding globulin were measured at baseline. Results: Baseline and peak LH responses to the agonist in late puberty and basal and peak FSH levels at all Tanner stages, were higher in girls than i n boys. Girls showed higher IGF-I levels than boys throughout puberty, shar per decreases in IGFBP-1 and earlier and greater increases in 17-hydroxypre gnenolone, dehydroepiandrosterone (DHEA) and DHEA-sulfate. Testosterone res ponses to the agonist increased during puberty in males, and showed no chan ges in females. Conversely estradiol responses rose throughout puberty in f emales and remained unchanged until late puberty in males. Conclusion: Leuprolide acetate stimulates gonadotropin and gonadal steroid secretion during puberty in both sexes and increases FSK levels in prepuber tal girls, Pubertal maturation of gonadotrope function is gender specific, as it appears to involve increases in both the releasable and reserve pools of LH in males, and of LH and FSH in females, The earlier increase in Delt a(5)-steroids in girls may suggest a sharper rise in ovarian cytochrome P45 0c17 activity along the Delta(5)-steroid pathway, while the failure of estr adiol to increase in response to leuprolide acetate in early pubertal males suggests a late maturation of aromatase activity.