14
Jul
Endocrine-Disrupting Chemicals Impair Juvenile Male Fertility Development and Threatens Future Reproductive Health
(Beyond Pesticides, July 14, 2022) A study published in Toxicology and Applied Pharmacology finds prepubescent exposure to endocrine-disrupting chemicals (EDCs), including pesticides, impairs male reproduction through the interruption of testicular homeostasis and development of reproductive Leydig cells. Endocrine disruptors are xenobiotic (i.e., chemical substances like toxic pesticides foreign to an organism or ecosystem). Many reports demonstrate that exposure to endocrine-disrupting chemicals can adversely affect human, animal—and thus environmental—health by altering the natural hormones in the body responsible for conventional reproductive, physical, and mental development. Scientists and health officials already associate pesticide exposure with a decrease in male fertility, including reduced sperm count, quality, and abnormal sperm development.
The presence of pesticides in the body has implications for human health, especially during vulnerable life stages, such as childhood, puberty, pregnancy, and old age. Therefore, it is essential to understand how exposure to toxic chemicals in the environment affects future reproductive success and health. The researchers note, “Recent studies revealed that exposures to EDCs during so-called critical windows of susceptibility (prenatal, prepubertal, pubertal, and aging periods) could disrupt healthy patterns of testes development and homeostasis, which can be demonstrated as an impaired testicular function later in life. However, much more work is needed to understand better the cellular and molecular mechanisms underlying EDC-induced effects in the male reproductive system during these critical periods of development.”
This study investigates how endocrine-disrupting chemicals play a role in the dysregulation of testicular gap junction intercellular communication (GJIC) in Leydig cells (the primary source of testosterone or androgens in males), resulting in reproductive toxicity. After evaluating cellular function and GJIC function through an assay, the researchers found methoxychlor, triclosan, triclocarban, lindane, and DDT immediately disrupt GJIC in Leydig cells through relocation of the protein connexin 43 (CX43) with prolonged (>24hours) exposure interrupting protein homeostasis (balance). The imbalance impairs the early stages of steroidogenesis (steroid generation) in prepubescent Leydig cells, impairing reproductive health later in life, post-puberty.
The ubiquity of pesticides in the environment and food supply is concerning as current measures restricting pesticide use and exposure do not adequately detect and assess total environmental chemical contaminants. For instance, 90 percent of Americans have at least one pesticide biomarker (including parent compound and breakdown products) in their body. The scientific literature demonstrates pesticides’ long history of severe adverse human health effects (i.e., endocrine disruption, cancer, reproductive/birth problems, neurotoxicity, loss of biodiversity, etc.). Most concerning is exposure to past and current-use pesticides, as these chemicals display endocrine-disrupting effects. The World Health Organization (WHO), European Union (EU), and endocrine disruptor expert (deceased) Theo Colborn, Ph.D., classify over 55 to 177 chemical compounds as endocrine disruptors, including various household products like detergents, disinfectants, plastics, and pesticides. Endocrine disruption can lead to several health problems, including hormone-related cancer development (i.e., thyroid, breast, ovarian, prostate, testicular), reproductive dysfunction, and diabetes/obesity that can span generations. Therefore, studies related to pesticides and endocrine disruption help scientists understand the underlying mechanisms that indirectly or directly cause infertility, among other health issues.
This study finds that endocrine disrupting chemicals impact protein accumulation in reproductive cells, rather than produce cytotoxic (toxic to living cells) effects. The accumulation of proteins because of EDC exposure deregulates junctional and non-junctional functions responsible for male reproductivity. Moreover, accumulation of protein CX43 in the endosomes from the junctional membrane of Leydig cells contribute to tumor formation. The study attributes the immediate dysregulation of testicular GJIC and CX43 function to EDCs that alter genomic signaling pathways and stimulates steroidogenesis disruption. Although this study specifically evaluates EDCs’ impacts on male fertility, this study is not the first to demonstrate the sex-specific effect of pesticide exposure. In 2017, scientists presented a study at the 99th meeting of the Endocrine Society, demonstrating instances of early onset puberty in boys after exposure to common pyrethroid insecticide, which exhibits endocrine disrupting properties that interfere with the proper regulation of the human body’s hormonal system. Furthermore, a 2021 study demonstrates that exposure to current-use pesticides, like organophosphates, poses a greater health risk to women. In addition to impacts on fertility, the study warns, “Testicular GJIC and connexin dysregulation, especially during critical early stages of development, could partly participate in the etiopathology of human subfertility and infertility and testicular cancer.”
Pediatricians agree that young children should avoid pesticide exposure during critical periods of development. Various pesticide products act similarly or in conjunction with other chemicals. Individuals can encounter these substances simultaneously, resulting in more severe health outcomes. Therefore, advocates urge that policies enforce stricter pesticide regulations and increase research on the long-term impacts of pesticide exposure. Beyond Pesticides tracks the most recent studies on pesticide exposure through our Pesticide-Induced Diseases Database (PIDD). This database supports the clear need for strategic action to shift from pesticide dependency. For more information on the multiple harms that pesticides can cause, see PIDD pages on Endocrine Disruption, Cancer, Birth/Fetal Effects, and other diseases.
Beyond Pesticides advocates a precautionary approach to pesticide regulation and preventive practices in land management and agriculture by transiting to organic. Buying, growing, and supporting organic helps to eliminate the extensive use of pesticides in the environment and your diet. For more information on how organic is the right choice for consumers and the farmworkers who grow our food, see the Beyond Pesticides webpage, Health Benefits of Organic Agriculture.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
