Developmental changes in testicular sensitivity to DES throughout fetal life

In vitro incubation of rat fetal testes with DES reduces testosterone production and the number of gonocytes by inhibiting proliferation and increasing apoptosis

2007 Study Abstract

There is now compelling evidence that inappropriate exposure to estrogen during fetal or neonatal life could affect adult reproductive functions because the testis is sensitive to estrogens during specific periods of its development.

Therefore, we investigated the effects of exogenous estrogens on gametogenesis and steroidogenesis during fetal and neonatal testicular development in the rat. We used in vitro systems, organ cultures, and dispersed testicular cell cultures, which allow the development of fetal and neonatal germ cells (gonocytes) and Leydig cells.

Exogenous estrogens inhibited testosterone production in dispersed testicular cell cultures throughout fetal life, but this inhibition was observed only in the early fetal stages in organ culture.

By using an aromatase inhibitor (letrozole, Novartis Pharma AG), we showed that the inhibitory effect of exogenous estrogens on testosterone production is masked in the whole testis at later stages (20.5 days postconception) due essentially to local production of estrogens. In both systems, additions of high concentrations (10(-6) M) of 17beta-estradiol or diethylstilbestrol decreased the number of gonocytes during the first fetal proliferative period but not during the neonatal period. Letrozole was without effect, suggesting that the aging-related loss of responsiveness of gonocytes is not due to any aromatase activity in the gonocytes.

Sources and more information
  • Full text (free access) : Developmental Changes in Testicular Sensitivity to Estrogens throughout Fetal and Neonatal Life, Toxicological sciences : an official journal of the Society of Toxicology, NCBI PubMed PMID: 17569695, 2007 Sept.
  • Testicular cells featured image credit the new jersey male infertility center.

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