Exercise Increases Serum Fibroblast Growth Factor 21 (FGF21) Levels

Fibroblast growth factor 21 (FGF21) increases glucose uptake. It is unknown if FGF21 serum levels are affected by exercise.This was a comparative longitudinal study. Anthropometric and biochemical evaluation were carried out before and after a bout of exercise and repeated after two weeks of daily supervised exercise. The study sample was composed of 60 sedentary young healthy women. The mean age was 24±3.7 years old, and the mean BMI was 21.4±7.0 kg/m². The anthropometric characteristics did not change after two weeks of exercise. FGF21 levels significantly increased after two weeks of exercise (276.8 ng/l (142.8-568.6) vs. (460.8 (298.2-742.1), p<0.0001)). The delta (final-basal) log of serum FGF21, adjusted for BMI, showed a significant positive correlation with basal glucose (r = 0.23, p = 0.04), mean maximal heart rate (MHR) (r = 0.54, p<0.0001), mean METs (r = 0.40, p = 0.002), delta plasma epinephrine (r = 0.53, p<0.0001) and delta plasma FFAs (r = 0.35, p = 0.006). A stepwise linear regression model showed that glucose, MHR, METs, FFAs, and epinephrine, were factors independently associated with the increment in FGF21 after the exercise program (F = 4.32; r² = 0.64, p<0.0001).Serum FGF21 levels significantly increased after two weeks of physical activity. This increment correlated positively with clinical parameters related to the adrenergic and lipolytic response to exercise.ClinicalTrials.gov NCT01512368

Flow chart of the study protocol.

<p>Flow chart of the study protocol.</p

Clinical and biochemical parameters of the sample studied before and after two weeks of supervised physical activity (n = 60).

<p>Data are expressed as mean±SD or as median (interquartil range). NS = not significant. SBP = systolic blood pressure; DBP = diastolic blood pressure; BMI = body mass index; WHR = waist-hip-ratio; ALT = alanine aminotransfarase; AST = aspartate aminotransferase; LDL-C = low-density lipoprotein cholesterol; HDL-C = high-density lipoprotein cholesterol; GGT = gamma-glutamyltransferase.</p>*<p>Daily physical activity measured with questionnaire.</p

Comparisons of biochemical parameters before and after supervised physical activity (n = 60).

<p>Data are expressed as mean±SD or as median (interquartil range). FGF21 was log-transformed before analysis. NS = not significant. BMI = body mass index; WC = waist circumference; FFAs = free fatty acids.</p>*<p>Bonferroni adjustment for multiple comparisons. Parameters of the repeated measures model of: Glucose: Hotteling's trace = 0.33; F = 3.29; p = 0.034; Insulin: Hotteling's trace = 1.80; F = 18.01; p<0.0001; FGF21: Hotteling's trace = 2.62; F = 22.76; p<0.0001; FFAs: Hotteling's trace = 1.58; F = 13.2; p<0.0001; Leptin: Hotteling's trace = 0.96; F = 10.93; p<0.0001; Epinephrine: Hotteling's trace = 2.29; F = 19.13; p<0.0001; Adiponectin: Hotteling's trace = 0.17; F = 1.98; p = 0.135.</p

Correlation of the log delta FGF21 (final-basal) levels with METs (A), delta epinephrine (B), and delta free fatty acids (C) in 60 women after two weeks of supervised physical activity.

<p>Correlation of the log delta FGF21 (final-basal) levels with METs (A), delta epinephrine (B), and delta free fatty acids (C) in 60 women after two weeks of supervised physical activity.</p

Correlations of the DELTA log FGF21 (final-basal) with the delta and mean values of related parameters associated with physical activity, lipolysis and adrenergic response (n = 60).

<p>FGF21 was log-transformed before analysis. All the correlations were adjusted for BMI. FGF21 = Fibroblast Growth Factor 21 (ng/l); RHR = Rest heart rate; MHR = Maximum heart rate; METs = Metabolic equivalents; FFA = Free fatty acids;</p>*<p>p<0.05;</p>**<p>p<0.01.</p