Eureka 2019: Unlocking the Secrets of FGF21

For the fifth year in a row, Endocrine News spoke with editors from Endocrine Society journals to get the scoop on the top endocrine discoveries of 2019. Here is part 3 of Eureka! 2019.

Endocrinology associate editor David Grattan, PhD, BSc, professor of neuroendocrinology at the University of Otago in Dunedin, New Zealand chose “Fibroblast Growth Factor-21 Controls Dietary Protein Intake in Male Mice,” by Ryan, K.K., et. al. from May.

“What I liked about this study was that it provided an insight into a previously unrecognized neuroendocrine feedback pathway regulating dietary protein intake.”

In this study, researchers uncover the neuroendocrine mechanism that regulates dietary protein, which is not stored, unlike carbohydrates and fats. They propose that fibroblast growth factor-21 (FGF21), which is secreted in response to low protein or amino acid levels, is the likely candidate and conducted experiments to determine whether FGF21 would induce intake of carbohydrates or protein in male mice. FGF21 increased protein intake, while reducing carbohydrate and fat intake. The study suggests that hepatic FGF21 is secreted in times of protein restriction, but not carbohydrate and fat restriction, signaling the brain that protein is needed.

“What I liked about this study was that it provided an insight into a previously unrecognized neuroendocrine feedback pathway regulating dietary protein intake. In doing so, it provided a clear explanation of the functions of a liver-derived hormone (FGF-21) that had been known about for some time, but for which a physiological context was lacking,” Grattan explains. “Here they showed that the hormone was secreted in response to low protein, and that it acts in the brain to promote preferential intake of protein over carbohydrates, thereby restoring macronutrient balance.”