TY - JOUR

T1 - Postnatal Changes in Testicular Position Are Associated With IGF-I and Function of Sertoli and Leydig Cells

AU - Koskenniemi, Jaakko J

AU - Virtanen, Helena E

AU - Wohlfahrt-Veje, Christine

AU - Löyttyniemi, Eliisa

AU - Skakkebaek, Niels E

AU - Juul, Anders

AU - Andersson, Anna-Maria

AU - Main, Katharina M

AU - Toppari, Jorma

PY - 2018

Y1 - 2018

N2 - 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, and 7 years and reproductive hormones at 3 months were measured.Setting: Prenatally recruited, prospective longitudinal birth cohort.Participants: A total of 2545 boys were recruited prenatally in a Danish-Finnish birth cohort and had a 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 3 months.Main Outcome Measures: Testicular distance to pubic bone (TDP), serum reproductive hormone, and IGF-I concentrations.Results: TDP increased from birth to 3 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/follicle-stimulating hormone ratio, and testosterone/luteinizing hormone ratio were all independently and positively associated with longer TDP.Conclusions: We provide 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 mini-puberty of infancy. TDP may thus be a useful biomarker of postnatal testicular function.

AB - 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, and 7 years and reproductive hormones at 3 months were measured.Setting: Prenatally recruited, prospective longitudinal birth cohort.Participants: A total of 2545 boys were recruited prenatally in a Danish-Finnish birth cohort and had a 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 3 months.Main Outcome Measures: Testicular distance to pubic bone (TDP), serum reproductive hormone, and IGF-I concentrations.Results: TDP increased from birth to 3 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/follicle-stimulating hormone ratio, and testosterone/luteinizing hormone ratio were all independently and positively associated with longer TDP.Conclusions: We provide 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 mini-puberty of infancy. TDP may thus be a useful biomarker of postnatal testicular function.

KW - Anthropometry

KW - Child

KW - Child, Preschool

KW - Denmark

KW - Finland

KW - Follicle Stimulating Hormone/blood

KW - Humans

KW - Infant

KW - Infant, Newborn

KW - Inhibins/blood

KW - Insulin-Like Growth Factor I/metabolism

KW - Longitudinal Studies

KW - Luteinizing Hormone/blood

KW - Male

KW - Penis/anatomy & histology

KW - Pubic Bone/anatomy & histology

KW - Testis/anatomy & histology

KW - Testosterone/blood

U2 - 10.1210/jc.2017-01889

DO - 10.1210/jc.2017-01889

M3 - Journal article

C2 - 29408984

VL - 103

SP - 1429

EP - 1437

JO - Journal of Clinical Endocrinology and Metabolism

JF - Journal of Clinical Endocrinology and Metabolism

SN - 0021-972X

IS - 4

ER -