The "fasting hormone" significantly increases life expectancy
Scientists at the University of Texas Southwestern Medical Center, working under the guidance of Professor Steven Kliewer, have found that the so-called fasting hormone significantly increases the lifespan of mice without limiting the caloric content of the diet.
Fibroblast Growth Factor-21 (FGF21) is a hormone secreted by the liver during periods of fasting in order to help the body adapt to a lack of nutrients. It is one of the three growth factors that behave like hormones, and therefore are considered atypical.
The results of a number of studies indicate that a low-calorie diet increases the life expectancy of different animal species. In experiments on transgenic mice, the authors demonstrated that increased production of the fibroblast growth factor hormone-21 has a similar effect without the need to reduce the amount of calories consumed. Hyperproduction of this hormone increased the average life expectancy of male mice by about 30%, and females by 40%.
In the figure from the article by Yuan Zhang et al. The starvation hormone, fibroblast growth factor-21, extends lifespan in mice, published in the journal eLife, shows the dynamics of mortality in wild-type transgenic mice (blue curves) and transgenic mice with elevated FGF21 levels (red). A – data for both sexes, B and C – for males and females.
The average life expectancy was taken to be the period after which half of the animals of the group in question remained alive. The experiment to assess the effect of the hormone on the maximum life expectancy continues to this day. According to preliminary data, none of the animals of the control group lived more than 3 years, while several females from the experimental group are alive at the age of almost 4 years.
Earlier studies have shown that FGF21 contributes to weight loss in obese mice. Mice with hyperproduction of this hormone used as a model in the last study remained thin throughout their lives, despite the fact that they consumed slightly more food than wild-type mice.
Apparently, the positive effects of this hormone are due to increased sensitivity of cells to insulin and blocking of the signaling mechanism mediated by growth hormone and insulin-like growth factor-1. According to researchers, excess growth hormone can contribute to the development of insulin resistance, cancer and other diseases.
However, FGF21 also has its negative sides. Its hyperproduction leads to a decrease in the body size of animals and infertility in females. Transgenic animals with hyperproduction of this hormone were also characterized by reduced bone density, but this did not affect their health. Such mice remained active until old age without cases of bone fractures.
According to Professor Cleaver, animals with increased FGF21 production live a full and very long life, however, reduced bone density and infertility of females require additional research to determine the possibility of selective use of the positive effects of the hormone.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of UT Southwestern:
Starvation hormone markedly extends mouse life span, researchers report.
18.10.2012