Endocrine disruptors: harmful for reproduction

According to new scientific work carried out in France, endocrine disruptors, and more precisely bisphenol A, alter fertility in mammals.

Disturbed neural functions

Early exposure to bisphenol A represents a health hazard. Individuals exposed from birth could experience disturbances in reproductive functions. This is the conclusion reached by researchers from the National Institute of Health and Medical Research (Inserm), as well as scientists from the Lille Neuroscience and Cognition laboratory. For 10 days after birth, they administered a small amount of bisphenol A to female rats. The results, published in the journal Nature Neuroscience, demonstrate that reproductive functions were disrupted in adulthood.

To understand the correlation between endocrine disruptors and fertility, it is necessary to know the regulatory system of hormones, especially in mammals. In the spleen, GnRH neurons are responsible for regulating reproduction. During the development of the embryo, these neuronal cells appear at the nasal level, then migrate to the brain before joining the hypothalamus. This population of neurons is essential not only for the proper functioning of reproduction, but also plays a role in all the processes associated with it, such as puberty and secondary sexual characteristics.

A detrimental impact on reproduction, the menstrual cycle and puberty

To fulfill their roles, GnRH neurons must attach themselves to other types of cells: astrocytes. This step is “ decisive for their integration into the neural network [qui] occurs during the so-called “mini-puberty” period. This phenomenon occurs one week after birth in female rats. However, as Inserm research director Vincent Prévot explains, “ Failure to integrate neurons into GnRH during mini-puberty can lead to a predisposition to develop puberty and / or fertility disorders, but also potentially affect brain development and thus lead to impaired functioning. learning or metabolic disorders such as overweight. »

Furthermore, this lack of link between the GnRH cells and the astrocytes may result in delayed puberty and lead to an absence of an estrous cycle in the rats, which corresponds to the menstrual cycle in women. As a result, reproductive functions are affected and impaired due to Bisphenol A.

However, is Bisphenol A not banned?

In theory, the use of bisphenol A has been banned since 2015 for the manufacture of baby bottles, bottles and certain food containers. Indeed, the Health Security Agency (ANSES), had shown in 2011 that exposure to this compound entailed health risks, in particular for pregnant women and the unborn child. Today, the deleterious effects of this endocrine disruptor are widely recognized. However, Vincent Prévot underlines that “ Despite its ban, bisphenol A is still present in our environment due to the slow degradation of plastic waste, but also because it is found in food containers purchased before 2015 and which have been preserved. With the recycling of waste, bisphenol A contained in plastics dating from before 2015 could also be found in new products. »

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