title: Fructose ingestion acutely stimulates circulating FGF21 levels in humans.
abstract: OBJECTIVE
  Fibroblast growth factor 21 (FGF21) is a hormone with pleiotropic metabolic activities which, in rodents, is robustly regulated by fasting and ketogenic diets. In contrast, similar dietary interventions have either no or minimal effects on circulating FGF21 in humans. Moreover, no intervention or dietary challenge has been shown to acutely stimulate circulating FGF21 in either humans or animals. Recent animal data suggest that the transcription factor Carbohydrate Responsive-Element Binding Protein (ChREBP) stimulates hepatic FGF21 expression and that fructose may activate hepatic ChREBP more robustly than glucose. Here, we examined whether fructose ingestion can acutely stimulate FGF21 in humans.
  
  
  METHODS
  We measured serum FGF21, glucose, insulin, and triglyceride levels in ten lean, healthy adults and eleven adults with the metabolic syndrome following oral ingestion of 75 g of glucose, fructose, or a combination of the two sugars.
  
  
  RESULTS
  FGF21 levels rose rapidly following fructose ingestion, achieved a mean 3.4-fold increase at two hours (P < 0.01), and returned to baseline levels within five hours. In contrast, FGF21 did not increase in the first two hours following ingestion of a glucose load, although more modest increases were observed after three to four hours. Both baseline and fructose-stimulated FGF21 levels were 2-3 fold elevated in subjects with metabolic syndrome.
  
  
  CONCLUSIONS
  Fructose ingestion acutely and robustly increases serum FGF21 levels in humans in a pattern consistent with a hormonal response. While FGF21 appears to be critical for the adaptive response to fasting or starvation in rodents, these findings suggest that in humans, FGF21 may play an important role in fructose metabolism.
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.
authors: Jody R
authors: JR
authors: Dushay
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.
authors: Elena
authors: E
authors: Toschi
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.
authors: Emilie K
authors: EK
authors: Mitten
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.
authors: Ffolliott M
authors: FM
authors: Fisher
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA ; Broad Institute, Cambridge, MA 02142, USA.
authors: Mark A
authors: MA
authors: Herman
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA ; Broad Institute, Cambridge, MA 02142, USA.
authors: Eleftheria
authors: E
authors: Maratos-Flier
keywords: ChREBP; FGF21; Fructose; Metabolic syndrome