What determines the growth rate of a child?

Scientists have determined how a protein in the brain uses information about the body's energy balance to regulate the growth rate of children and the onset of puberty

The study is planned to be published in the journal Nature on November 3, and the focus of the research is on the melanocorticoid 3 receptor (MC3R), which is a member of a protein family that has long been considered It plays an important role in metabolism and energy balance

Physiologist Roger Cone of the University of Michigan and his colleagues discovered the MC3R gene more than 20 years ago and proved that mice lacking this protein have linearly reduced growth

Now, an international team of scientists led by Stephen O'Rahilly of the Institute of Metabolic Sciences at the University of Cambridge has revealed for the first time how defects in MC3R are transformed into humans—the results are surprisingly similar to those found in mice

The O'Rahilly team reported the first person to have mutations in both copies of the MC3R gene, which made his MC3R lose its function

Using data from the British Biobank and the Longitudinal Study of Children, the team analyzed the phenotype of a mutation in a copy of the MC3R encoding gene in volunteers

"In terms of melanocorticoids, every phenotype we observed in mice was eventually found to be replicated in humans," Cone said.

In addition, O'Rahilly discovered a new phenotype in people with MC3R mutations: in patients lacking MC3R, there is a long delay in the onset of puberty, while in volunteers from the British Biobank, there is only one gene.

New data generated by Richard Simely, a collaborator of Cone Lab and Vanderbilt Medical School, published in this latest study, confirms this effect and believes that MC3R plays a role in conveying nutrient deprivation to the reproductive axis

When the mice fasted for 24 hours, MC3R detected insufficient energy storage in the body and relayed the information to the part of the brain responsible for regulating the reproductive cycle

"These types of experiments give us important new insights into the human body's metabolism and reproductive pathways, but obviously they cannot be performed on humans," Cone said.

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MC3R links nutritional state to childhood growth and the timing of puberty