Obesity

Site of Leptin Hormone in the Brain Identified

Experts from the UT Southwestern Medical Center have succeeded in identifying the location in the brain where leptin, a hormone produced by fat cells, triggers the onset of puberty in females. Puberty onsets in a female body only when there are enough fat reserves to meet the demands of giving birth to a baby. Since leptin is produced by fat cells, researchers have long known that it plays an important role in pubertal onset, however the site of action has only recently been discovered.

In addition to discovering its role in female puberty, researchers are also interested in leptin for its role in obesity. It has been clearly documented in numerous studies that leptin is partially responsible for controlling human appetite and food intake. The more knowledge that scientists have about leptin and its points of action in the brain, the closer they are to finding a possible way to help treat obesity and control food intake. This study by UT Southwestern Medical Center* helps shed light on where leptin acts in the brain.

*Researchers from Rockefeller University, the University of Säo Paulo, the Albert Einstein College of Medicine and Acceleron Pharma were also participants in this study which was funded by the National Institutes of Health and other research foundations.

What does Research Reveal About Leptin Hormone and the Onset of Puberty?

  • A small portion of the hypothalamus, known as the ventral premammillary nucleus (PMV) is the site in the brain where this hormone triggers puberty in females.
  • Though it is believed that there are other sites in the brain which play roles in triggering and starting puberty, the present research further clarifies the role leptin plays as a signaling molecule for starting the process.
  • Earlier studies on this subject have shown that low levels of this hormone in the body delays puberty and may cause females to be infertile.
  • It is speculated that obese children have an early onset of puberty because the fat cells produce excessive amounts of leptin.
  • Introducing leptin hormone in children who were deficient in it led to onset of puberty, further strengthening the relationship between leptin and pubertal onset.
  • In the present research, experts created experimental mice in the laboratory that had this hormone only in the PMV and no where else in the body.
  • It was observed that though these female mice were obese, they had the onset of puberty and became pregnant too.
  • The finding that the presence of this hormone in the PMV is sufficient to trigger puberty and fertility was surprising to the researchers.

Conclusion:

Of many other reasons, leptin is a hormone of interest in the medical community because of the close tie it has with female pubertal onset and obesity. The discovery of where leptin acts in the brain is a huge step forward in leptin research, one which may help scientists find ways to control how the human body reacts to this hormone. Controlling leptin and its action in the brain may help researchers discover a way to control obesity and fat deposition in the body. More research is needed for this and to uncover the role leptin plays in influencing male puberty, but this research is a big step in the right direction.

References

http://www.utsouthwestern.edu/newsroom/news-releases/year-2010/ut-southwestern-researchers-identify-site-in-brain-where-leptin-may-trigger-puberty.html
Zhao, S., et al. “Hindbrain leptin and glucagon-like-peptide-1 receptor signaling interact to suppress food intake in and additive manner.” International Journal of Obesity. 2012. doi:10.1038/ijo.2011.265
http://www.ncbi.nlm.nih.gov/pubmed/12193563

Zhao, S., et al. “Hindbrain leptin and glucagon-like-peptide-1 receptor signaling interact to suppress food intake in and additive manner.” International Journal of Obesity. 2012. doi:10.1038/ijo.2011.265
http://www.ncbi.nlm.nih.gov/pubmed/12193563
http://jcem.endojournals.org/content/84/7/2270.full.pdf

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