Inhibin B, follicle stimulating hormone, luteinizing hormone, and estradiol and their relationship to the regulation of follicle development in girls during childhood and puberty

Abstract

Inhibin B, produced by granulosa cells in the ovary, is a heterodimeric glycoprotein suppressing synthesis and secretion of the follicle stimulating hormone (FSH). The aim of the present study was to determine hormone profiles of inhibin B, FSH, luteinizing hormone (LH), and estradiol in girls during childhood and puberty and to evaluate whether inhibin B is a marker of follicle development. We examined the correlation between inhibin B and gonadotropins and estradiol during the first two years and across the pubertal development. Using a specific two-side enzyme-linked immunosorbent assay (ELISA), inhibin B levels were measured in the serum of 53 healthy girls divided into 8 groups according to age. In addition, serum FSH, LH, and estradiol were measured by chemiluminescent immunoassay in all serum samples. A rise in serum levels of inhibin B (55.2±7.3 ng/l, mean ± S.E.M.) and FSH (1.78±0.26 UI/l), concomitant with a moderate increment of serum LH (0.36±0.09 UI/l) and estradiol (45.8±12.2 pmol/l) concentrations was observed during the first three months of life and declined to prepubertal concentrations thereafter. A strong positive correlation between inhibin B and FSH (r = 0.48, p<0.05), LH (r = 0.68, p<0.001) and estradiol (r = 0.59, p<0.01) was demonstrated during the first 2 years of life. A rise in serum levels of inhibin B, FSH, LH, and estradiol was found throughout puberty. Inhibin B had a strong positive correlation with FSH (stage I of puberty: r = 0.64, p<0.05; stage II of puberty: r = 0.86, p<0.01), LH (I: r = 0.61, p<0.05; II: r = 0.67, p<0.05), and estradiol (II: r = 0.62, p<0.05) in early puberty. From pubertal stage II, inhibin B lost this relationship to gonadotropins and estradiol. Serum inhibin B and FSH levels increased significantly during pubertal development, with the highest peak found in stage III of puberty (133.5±14.3 ng/l), and decreased thereafter. In conclusion, inhibin B is produced in a specific pattern in response to gonadotropin stimulation and plays an important role in the regulation of the hypothalamic-pituitary-gonadal axis during childhood and puberty in girls. Inhibin B is involved in regulatory functions in developing follicles and seems to be a sensitive marker of ovarian follicle development.

Age- and sex-dependent reference intervals of inhibin B in Chinese children on chemiluminescence analyzer

“…The normal values for serum INHB have been often assessed among adults, especially fertile and infertile adults [14][15][16] . However, few study has established sex-and age-related INHB reference data from birth to adulthood (n = 366, boys) 5 , aged 6-11years (n = 705, girls) 6 and during childhood and puberty (n = 52, girls) 13 in European and western countries. Due to the practical di cult in infant's recruitment, some studies may contain few infants or participants aged range of 5 ~ 18 years old.…”

“…However, RIs of serum INHB have not been required due to the effects of age, sex, methodologies and di culties in collecting ample serum from healthy children especially neonates. A few reports have investigated RIs of INHB based on enzyme-linked immunosorbent assays (ELISA), but they are the rough reference ranges from a small amount of children in European and western countries 5,6,13 or are acquired from the speci c enrolled subjects such as infertile couples 14 . There little is known about RIs of INHB in Chinese pediatric individuals, which hinders pediatric clinical use as a potential diagnostic marker.…”