“Restricting food intake has been shown to extend lifespan in several different kinds of animals. In our study, we found transgenic mice that produced more of the hormone fibroblast growth factor-21 (FGF21) got the benefits of dieting without having to limit their food intake. Male mice that overproduced the hormone had about a 30 percent increase in average life span and female mice had about a 40 percent increase in average life span,” said senior author Dr. Steven Kliewer, professor of molecular biology and pharmacology.
The study published online in eLife – a new peer-reviewed, open access journal – defined average life span as the point at which half the members of a given test group remained alive. A study to determine differences in maximum life span is ongoing: While none of the untreated mice lived longer than about 3 years, some of the female mice that overproduced FGF21 were still alive at nearly 4 years, the researchers report.
FGF21 seems to provide its health benefits by increasing insulin sensitivity and blocking the growth hormone/insulin-like growth factor-1 signaling pathway. When too abundant, growth hormone can contribute to insulin resistance, cancer, and other diseases, the researchers said.