Author:
Lundgaard Riis Malene,Matilionyte Gabriele,Nielsen John E.,Melau Cecilie,Greenald David,Juul Hare Kristine,Langhoff Thuesen Lea,Dreisler Eva,Aaboe Kasper,Brenøe Pia Tutein,Andersson Anna-Maria,Albrethsen Jakob,Frederiksen Hanne,Rajpert-De Meyts Ewa,Juul Anders,Mitchell Rod T.,Jørgensen Anne
Abstract
Abstract
Background
Reduced androgen action during early fetal development has been suggested as the origin of reproductive disorders comprised within the testicular dysgenesis syndrome (TDS). This hypothesis has been supported by studies in rats demonstrating that normal male development and adult reproductive function depend on sufficient androgen exposure during a sensitive fetal period, called the masculinization programming window (MPW). The main aim of this study was therefore to examine the effects of manipulating androgen production during different timepoints during early human fetal testis development to identify the existence and timing of a possible window of androgen sensitivity resembling the MPW in rats.
Methods
The effects of experimentally reduced androgen exposure during different periods of human fetal testis development and function were examined using an established and validated human ex vivo tissue culture model. The androgen production was reduced by treatment with ketoconazole and validated by treatment with flutamide which blocks the androgen receptor. Testicular hormone production ex vivo was measured by liquid chromatography-tandem mass spectrometry or ELISA assays, and selected protein markers were assessed by immunohistochemistry.
Results
Ketoconazole reduced androgen production in testes from gestational weeks (GW) 7–21, which were subsequently divided into four age groups: GW 7–10, 10–12, 12–16 and 16–21. Additionally, reduced secretion of testicular hormones INSL3, AMH and Inhibin B was observed, but only in the age groups GW 7–10 and 10–12, while a decrease in the total density of germ cells and OCT4+ gonocytes was found in the GW 7–10 age group. Flutamide treatment in specimens aged GW 7–12 did not alter androgen production, but the secretion of INSL3, AMH and Inhibin B was reduced, and a reduced number of pre-spermatogonia was observed.
Conclusions
This study showed that reduced androgen action during early development affects the function and density of several cell types in the human fetal testis, with similar effects observed after ketoconazole and flutamide treatment. The effects were only observed within the GW 7–14 period—thereby indicating the presence of a window of androgen sensitivity in the human fetal testis.
Funder
International Centre for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health
Svend Andersen Fonden
The NEYE Foundation
Danish Environmental Protection Agency for projects under the Centre on Endocrine Disrupters
MRC Centre Grant
Publisher
Springer Science and Business Media LLC