ESPE2022 Rapid Free Communications Sex Development and Gonads (6 abstracts)
Background: The male Hypothalamic-Pituitary-Gonadal (HPG) axis is transiently active during the first months of life with surging serum concentrations of reproductive hormones. This period, termed minipuberty, promotes masculinization, including testicular, and penile growth, as well as further testicular descent in males. It appears to be essential for priming specific cell types, i.e. Sertoli-, Leydig-, and germ cells, including subsequent growth and maturation. Despite the potential pivotal role of minipuberty on male reproductive function, comprehensive, longitudinal data on HPG axis activation with quantification of serum reproductive hormones dynamics as well as effects on target tissue are sparse.
Objective: We aimed to 1) explore the dynamics of HPG hormone activity in healthy male infants, 2) assess the association of HPG axis activity and testicular volume and 3) establish reference curves for serum levels of reproductive hormones.
Participants & Methods: In a prospective, longitudinal birth cohort (The COPENHAGEN Minipuberty Study, 2016-2018) we followed healthy, term, singleton newborns from birth onwards with repeated clinical examinations including blood sampling during a one-year follow-up. For this study, we included a total of 128 boys of which 119 participated in the postnatal follow-up. Serum reproductive hormone concentrations and testicular volume were measured
Results: We provide reference curves for follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, insulin-like factor 3 (INSL3), Inhibin B, anti-Müllerian hormone (AMH), and sex hormone-binding globulin (SHBG) in healthy boys during the first year of life. Reproductive hormone concentrations showed marked dynamics during the first six months of age. FSH, LH, testosterone and INSL3 peaked at around one month of age. This represents a distinct difference to Inhibin B, AMH and testicular volume that peaked at around 4-5 months.
Conclusions: We provide reference curves for reproductive hormones in boys during the first year of life and demonstrate a temporal dissociation of Leydig- and Sertoli cell activity during male minipuberty. Our study provides a valuable resource for clinicians evaluating infants with suspected reproductive disorders.
15 Sep 2022 - 17 Sep 2022