May 28, 2019

It’s not just something your grandma says—everyone is growing up faster than they used to.

Over the past 150 years, the average onset of puberty has been steadily declining. A century and a half ago, girls reached reproductive competence around 17.5 years of age—but now, the average age is 12.5 years. Early-onset puberty can lead girls to experience health problems later, including increased incidence of ovarian, uterine and breast cancers, as well as being at a higher risk for cardiovascular and metabolic diseases.

Researchers at the Oregon National Primate Research Center (ONPRC) at Oregon Health & Science University (OHSU) and the University of Pittsburgh wondered what was causing this increase in early bloomers. Their research led to the discovery of potential genetic causes, such as those of genes in the Zinc finger (ZNF) group, which serve as a “neurobiological brake” and delay puberty until the end of childhood development. Without this biological pause button, developing kids would be more susceptible to cancer, cardiovascular disease, and metabolic disorders.

Scientists also hypothesize diet could be a large contributing factor to early onset puberty. Researchers at the ONPRC, in conjunction with the University of Cordoba in Spain, sought to investigate this hypothesis in a recent study.

“Deepening our understanding of how the brain controls the initiation of puberty will allow us to understand why girls are initiating puberty at much earlier ages,” said Dr. Alejandro Lomniczi, lead researcher on the study and assistant professor for the Division of Genetics at the ONPRC.

Focusing on the hypothalamus, the ventral part of the brain which controls reproductive development, Lomniczi and colleagues identified the enzyme SIRT1 in the hypothalamus as a key player in the transmission of body weight information to the brain. In overweight animals, there is less SIRT1 in the hypothalamus, allowing what is known as the Kiss1 gene to be expressed earlier, leading animals to undergo puberty sooner. In underfed animals, SIRT1 is higher for a prolonged period of time, causing Kiss1 gene activation to take longer and delaying puberty.

With these discoveries guiding their work, researchers can optimize how they study puberty—another step forward in the work to help people live longer, healthier lives.

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