Sex differences in FSH‐regulatory peptides in pubertal age boys and girls and effects of sex steroid treatment

• Published in: Human reproduction (Oxford) Vol. 19; no. 7; pp. 1668 - 1676
• Main Authors: Foster, Carol M., Olton, Pamela R., Racine, Michael S., Phillips, David J., Padmanabhan, Vasantha
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.07.2004; Oxford Publishing Limited (England)
• Subjects: activin/follistatin/FSH/inhibin/puberty; Activins - blood; Adolescent; Aging - blood; Biological and medical sciences; Child; Embryology: invertebrates and vertebrates. Teratology; Estradiol - therapeutic use; Female; Follicle Stimulating Hormone - secretion; Fundamental and applied biological sciences. Psychology; Gonadal Steroid Hormones - therapeutic use; Humans; Inhibin-beta Subunits - blood; Inhibins - blood; Male; Puberty - blood; Sex Characteristics; Testosterone - therapeutic use; Turner Syndrome - drug therapy; Turner Syndrome - metabolism; activin/follistatin/FSH/inhibin/puberty; Steroid; Vertebrata; Mammalia; Treatment; Adenohypophyseal hormone; Peptides; Sex; Gonadotropin; Sexual dimorphism; Age; Follicle stimulating hormone
• ISSN: 0268-1161; 1460-2350; 1460-2350
• DOI: 10.1093/humrep/deh284

BACKGROUND: FSH concentrations are higher in girls than in boys before puberty. We hypothesized that steroid‐mediated changes in FSH‐regulatory proteins underlie the sex differences in FSH secretion and pubertal timing. METHODS: FSH‐regulatory proteins, LH, FSH and sex steroids were measured in five boys, 10 girls, and five girls with Turner syndrome before and during sex steroid treatment (girls, 0.05 mg/day estradiol; boys, 5 mg/day testosterone) for up to 4 weeks. Blood was obtained every 15 min from 20.00 to 08.00 h before and during sex steroid treatment. RESULTS: The mean FSH concentration was higher in girls than in boys (P = 0.0044). Activin‐A concentrations were greater (P < 0.0001) and inhibin‐B concentrations lower (P < 0.0001) in girls compared with boys. Steroid treatment (i) suppressed LH/FSH concentrations in all subjects; (ii) increased the mean activin‐A concentration in all but the Turner girls (P = 0.001); and (iii) decreased inhibin‐B concentrations in boys (P = 0.005) but not in girls. Total follistatin and follistatin 288 concentrations did not differ by sex. CONCLUSIONS: Sex steroids regulate circulating activin‐A and inhibin‐B concentrations in children. The lower inhibin‐B and higher activin‐A concentrations may explain the higher FSH and earlier onset of puberty in girls.