Serum levels of insulin-like factor 3, anti-Mullerian hormone, inhibin B, and testosterone during pubertal transition in healthy boys: a longitudinal pilot study.
Insulin-like factor 3 (INSL3) is a promising marker of Leydig cell function with potentially high clinical relevance. Limited data of INSL3 levels in relation to other reproductive hormones in healthy pubertal boys exist. In this study, we aimed to evaluate longitudinal serum changes in INSL3 compared with LH, FSH, testosterone, inhibin B, and anti-Müllerian hormone (AMH) during puberty in healthy boys. Ten boys were included from the longitudinal part of the COPENHAGEN Puberty Study. Pubertal evaluation, including testicular volume, was performed and blood samples were drawn every 6 months for 5 years. Serum concentrations of testosterone were determined by a newly developed LC-MS/MS method, and serum concentrations of INSL3, AMH, inhibin B, FSH, and LH respectively were determined by validated immunoassays. The results showed that serum INSL3 levels increased progressively with increasing age, pubertal onset, and testicular volume. In six of the ten boys, LH increased before the first observed increase in INSL3. In the remaining four boys, the increase in LH and INSL3 was observed at the same examination. The increases in serum concentrations of LH, testosterone, and INSL3 were not parallel or in ordered succession and varied interindividually. We demonstrated that INSL3 concentrations were tightly associated with pubertal onset and increasing testicular volume. However, the pubertal increases in LH, INSL3, and testosterone concentrations were not entirely parallel, suggesting that INSL3 and testosterone may be regulated differently. Thus, we speculate that INSL3 provides additional information on Leydig cell differentiation and function during puberty compared with traditional markers of testicular function.
Department of Growth and Reproduction, GR 5064, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Oslash;, Denmark.
Marie Lindhardt
ML
Johansen
Ravinder
R
Anand-Ivell
Annette
A
Mouritsen
Casper P
CP
Hagen
Mikkel G
MG
Mieritz
Tue
T
Søeborg
Trine Holm
TH
Johannsen
Katharina M
KM
Main
Anna-Maria
AM
Andersson
Richard
R
Ivell
Anders
A
Juul
D000293:Adolescent; D054304:Anti-Mullerian Hormone / Q000097:blood*; D002648:Child; D006262:Health; D006801:Humans; D007265:Inhibins / Q000097:blood*; D007328:Insulin / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D010865:Pilot Projects; D011506:Proteins; D011627:Puberty / Q000097:blood*; D012741:Sexual Maturation; D013739:Testosterone / Q000097:blood*
D007328:Insulin; C084797:Leydig insulin-like protein; D011506:Proteins; C422364:inhibin B; D013739:Testosterone; D007265:Inhibins; D054304:Anti-Mullerian Hormone