Transgenerational Epigenetic Inheritance: Focus on Endocrine Disrupting Compounds

2014 Study Abstract

The classic case of an EDC is diethylstilbestrol (DES), an estrogen agonist and androgen receptor antagonist synthesized first in the 1930s and prescribed to at least 5 million women at risk for miscarriage or experiencing other reproductive problems, from 1938 up to 1975. Instead of the desired effects, use of this compound lead to increased incidence of breast, vaginal, and cervical cancers.

In addition, maternal exposure has documented adverse affects on daughters. These include the same types of cancers as well as a variety of difficulties conceiving and maintaining pregnancies, reproductive tract malformations, abnormal menstrual cycles, early puberty, and behavioral issues. The vast variety of effects is probably related to complexities introduced by the timing of DES treatment and doses. For example, a recent large study of women exposed prenatally to DES revealed a strong correlation between DES, particularly in the first trimester, and noncancerous uterine fibroids. Offspring of rodents exposed to DES during pregnancy recapitulate many of these effects.

Although the initial clinical studies were limited to female offspring, correlations between DES exposure and hypospadias, cryptorchidism, and testicular cancer have been reported in F1 and F2 sons and grandsons of women given DES. Analyses of the clinical studies suggest that the male reproductive illnesses are related to but not necessarily caused by estrogen actions. An alternative hypothesis is that DES produces low-birth-weight babies, and these infants are more prone to testicular dysgenesis syndrome. Multigenerational work in mice has demonstrated that high, but clinically relevant, doses of DES increase the incidence of uterine and other reproductive tract tumors in females and lesions in the male rete testes in F2 offspring. Few data on the critical F3 generation in humans are available nor are there experimental data from rodent models.

EDCs, such as DES, share many properties with steroid hormones: they act at low doses (picograms) and can act in a nonmonotonic manne. Like hormones, they are particularly effective during development, at which time they can modify the course of reproductive tract and brain development. Importantly, the EDCs are more promiscuous than steroids and bind to a larger variety of receptors than normal ligands, albeit with reduced affinities.

Sources

  • Transgenerational Epigenetic Inheritance: Focus on Endocrine Disrupting Compounds, Endocrinology, NCBI PubMed PMC4098001, 2014 Aug.
  • Featured image Matt Artz.
DES DIETHYLSTILBESTROL RESOURCES

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