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

Abstract

Objective: To assess whether the maturational changes of the pituitary-gonadal axis in a healthy population show gender-specific changes and to establish normative data for the different Tanner stages. Design: Prospective, cross-sectional study. Methods: The GnRH agonist leuprolide acetate (500 mg) was administered s.c. to 60 boys and 81 girls (age range, 5-17 years). Serum steroids and gonadotropins were determined at 0 and 24 h and at 0, 3 and 24 h after GnRH agonist challenge respectively, whereas IGF-I, IGF-binding protein-1 (IGFBP-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 in boys. Girls showed higher IGF-I levels than boys throughout puberty, sharper decreases in IGFBP-1 and earlier and greater increases in 17-hydroxypregnenolone, dehydroepiandrosterone (DHEA) and DHEA-sulfate. Testosterone responses to the agonist increased during puberty in males, and showed no changes in females. Conversely, estradiol responses rose throughout puberty in females and remained unchanged until late puberty in males. Conclusion: Leuprolide acetate stimulates gonadotropin and gonadal steroid secretion during puberty in both sexes and increases FSH levels in prepubertal 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 D 5-steroids in girls may suggest a sharper rise in ovarian cytochrome P450c17 activity along the D 5-steroid pathway, while the failure of estradiol to increase in response to leuprolide acetate in early pubertal males suggests a late maturation of aromatase activity.

Response to the gonadotropin releasing hormone agonist leuprolide in immature female sheep androgenized in utero

“…Leuprolide has been used in human and animal studies. In boys and girls, leuprolide acetate stimulates gonadotropin and gonadal steroid secretion during puberty in both sexes (Potau et al, 1999).The results from the present study indicate that the GnRH agonist stimulated both the pituitary gland and the ovary in both groups. The sensitivity of the pituitary gland to the leuprolide challenge (measured as AUC of LH) differed between the control and T-females.…”

Efficacy and Safety of Gonadotropin-Releasing Hormone Agonist Treatment to Suppress Puberty in Gender Dysphoric Adolescents

“…Lower FSH levels also have been found in healthy boys compared with girls, prepubertally and during puberty, and in the basal state and in response to GnRH. 18 This might be due to sexually dimorphic development or programming of the hypothalamus-pituitary-gonadal axis, for example, by prenatal sex steroids.…”

Absent or Delayed Adrenarche in Pit-1/POU1F1 Deficiency

“…DHEAS results are also expressed in standard deviation scores (SDS) derived from published norms for age, gender and pubertal stage [21]. Hormonal data at diagnosis (cortisol, PRL, ACTH, GH) have been reported earlier [3, 8, 20], except for cases 3 and 4.…”