FGF21 is only a part of a complex network of proteins and hormones that affect metabolism and growth. But it appears to be a central part of the network, which may work as a key to unlock some important doors of understanding of metabolic diseases such as diabetes mellitus type 2, mechanisms of growth, as well as providing insights into the ageing process and diseases of ageing.
Fibroblast growth factor-21 (FGF21) is a hormone secreted by the liver during fasting that elicits diverse aspects of the adaptive starvation response. Among its effects, FGF21 induces hepatic fatty acid oxidation and ketogenesis, increases insulin sensitivity, blocks somatic growth and causes bone loss. Here we show that transgenic overexpression of FGF21 markedly extends lifespan in mice without reducing food intake or affecting markers of NAD+ metabolism or AMP kinase and mTOR signaling. Transcriptomic analysis suggests that FGF21 acts primarily by blunting the growth hormone/insulin-like growth factor-1 signaling pathway in liver. These findings raise the possibility that FGF21 can be used to extend lifespan in other species. _ eLifeThere are too many unanswered questions regarding the entire tapestry of hormones involved in growth, metabolism, and ageing, for scientists to recommend use of FGF21 in humans.
The relationship of FGF21 to diabetes and bone density must be teased out and better defined. An intriguing relationship between FGF21 and hibernation should also be better illuminated and clarified.
FGF21 is certainly not THE answer to ageing. But it is very likely to lead us to a number of better questions. And eventually, it may add a decade or two of healthy lifespan to people of the near future.