Postnatal Changes in Testicular Position are Associated with IGF-I and Function of Sertoli and Leydig Cells.

Postnatal Changes in Testicular Position are Associated with IGF-I and Function of Sertoli and Leydig Cells.

J Clin Endocrinol Metab. 2018 Feb 01;:

Authors: Koskenniemi JJ, Virtanen HE, Wohlfahrt-Veje C, Löyttyniemi E, Skakkebaek NE, Juul A, Andersson AM, Main KM, Toppari J

Abstract
Context: Despite clinical guidelines calling for repetitive examination of testicular position during childhood, little is known of normal changes in testicular position during childhood, let alone factors that control it.
Objective: To assess changes in, and factors associated with testicular position during childhood.
Design: Testicular position (the distance from the pubic bone to the upper pole of the testes) at birth, 3 months, 18 months, 36 months, 7 years and reproductive hormones at three months were measured.
Setting: Prenatally recruited, prospective longitudinal birth cohort.
Participants: In total 2545 boys were recruited prenatally in a Danish-Finnish birth cohort and had testicular position examination available. A subset of 680 Danish and 362 Finnish boys had serum reproductive hormone concentrations and insulin-like growth factor I (IGF-I) determined at three months.
Main Outcome Measures: Testicular distance to pubic bone (TDP), serum reproductive hormone and IGF-I concentrations.
Results: TDP increased from birth to three months, and decreased thereafter. Length, gestational age, weight for gestational age, and penile length were positively associated with larger TDP and thus lower testicular position in a linear mixed-effect model. Furthermore, IGF-I concentration, inhibin B/FSH-ratio, and testosterone/LH-ratio were all independently and positively associated with longer TDP.
Conclusions: We provide the first longitudinal data on postnatal changes in TDP. TDP is dynamic and associated with Leydig and Sertoli cell function as well as with IGF-I levels during the first months of life at minipuberty of infancy. TDP may thus be a useful biomarker of postnatal testicular function.

PMID: 29408984 [PubMed - as supplied by publisher]

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