This Wednesday, the National Institute of Health and Medical Research (INSERM) communicated around the discovery of one of its research teams on the mechanism of precocious puberty. Explanations.
- The prepubertal growth spurt would be controlled by GnRH neurons, contrary to the scientific consensus that existed on this point
- Better understanding and controlling the migration of these neurons to the brain would make it possible to limit precocious puberty
Why do some little girls have women’s breasts at just 10 years old? Precocious puberty is still a poorly understood phenomenon. According to the National Institute of Health and Medical Research (INSERM), the medical consensus was that a prepubertal growth spurt activates GnRH neurons which in turn acts on the ovaries and testicles thus causing puberty. But this Wednesday, September 17, Inserm echoes the publication a research article by one of their team, also working for Lille University Hospital and the University of Lille, published in The EMBO Journal on August 5. explaining that it is these GnRH neurons that would cause this growth spurt and not the reverse and that it is a disruption of these neurons that would be the cause of precocious puberty.
These results follow on from a previous study in which this research team had discovered that these neurons passed through the embryo from the cells of the nose to the brain thanks to the action of the Nrp1 protein at the base of the neurons between the nose and the brain but also present on GnRH neurons.
GnRH neurons: a link with weight gain?
To reach these conclusions, the researchers bred mice lacking Nrp1 at the level of GnRH neurons. There they observed that these GnRH neurons lacking Nrp1 are more numerous than normal, and that this embryonic migration between the nose and the brain occurs much more quickly. When these mice grow without Nrp1 at the level of GnRH neurons, they observe that they gain more weight, grow faster and have an earlier puberty. “We will look for connections and communications between GnRH neurons and appetite and growth regulation functions to explain this phenomenon.specifies Vincent Prévot director of the study. This is the first time to my knowledge that these GnRH neurons have been attributed with functions other than reproduction.”
Along with this migration from the nose to the early brain, the scientists observed that these GnRH neurons do not occupy the same place in the brain as mice where the Nrp1 was not deactivated from the GnRH neurons. Thus, the GnRH neurons of early mice lodge in the olfactory lobe of the brain and not the hypothalamus. The research team then noticed that these mice are more attracted to the smell of male mice than non-precocious mice of the same age. They speculate that these GnRH neurons also cause earlier sexual attraction as well.
A way to prevent precocious puberty
Can this work be transposed to humans? “These results suggest that a very early growth peak could be associated with an early activation of GnRH neurons. This phenomenon could, moreover, be associated with certain variants of the gene NRP1. These results open new avenues in the prevention of the risks of precocious puberty in children, assures Vincent Prévot. We are now going to explore the possibility of inhibiting the activity of GnRH neurons with drugs already used in the clinic..”
Early puberty promotes the onset of type 2 diabetes, gestational diabetes and cardiovascular disease. This body transformed too soon slows down growth and often imposes a femininity that young girls find difficult to cope with and sometimes requires hormonal or psychological help.
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