Page 96 - Human Bile Acid Metabolism: a Postprandial Perspective

Chapter 5
Experiment 2
The changes in GLP-1 and FGF19 and correlation between gDCA and insulin levels in experiment 1 prompted us to explore the effect of gDCA supplementation on these postprandial parameters.
Plasma glucose and insulin concentrations after gDCA administration.
Administration of gDCA had no effect on the total postprandial excursion of glucose (AUC0-240 –gDCA: 1,176.9 [173.0] mmol/L × min vs. +gDCA: 1,145.1 [63.3]; P > 0.05, 2-way RM-ANOVA P > 0.05) (Fig. 3A). Because the postprandial curve showed a glucose lowering effect after gDCA administration between T75 and T180, we calculated the AUC of glucose for these specific time points and we found that gDCA administration decreased the AUC75-180 before glucose levels returned to baseline (-gDCA: 616.5 [76.3] mmol/L × min vs. +gDCA: 544.4 [109.7]) mmol/L × min; P < 0.05). However, gDCA administration did not affect postprandial insulin concentrations (AUC0-240 –gDCA: 46,188.8 [30,275.9] vs. +gDCA 45,978.8 [4,4045.6] P > 0.05; 2-way RM-ANOVA P > 0.05) (Fig. 3B). Analyses of the iAUCs of glucose and insulin yielded the same results (data not shown).
Plasma BA concentrations after gDCA administration. TBA excursions after the test meal were not affected by gDCA administration (AUC0-240 -gDCA: 1,126.6 [621.0] μmol/L × min vs. +gDCA: 1,104.3 [686.7] μmol/L × min; P > 0.05, 2-way RM- ANOVA P > 0.05), although some differences in BA composition were uncovered (Table 1). In line with our expectations, postprandial gDCA concentrations (AUC) were increased after gDCA administration (AUC0-240 -gDCA: 152.0 [141.4] μmol/L × min vs. +gDCA: 231.1 [133.0] μmol/L × min, P < 0.05, 2-way RM-ANOVA P > 0.05) (Fig. 3C). Correlation analyses showed no significant correlations after gDCA administration. Analysis of the iAUC of TBAs yielded the same results (data not shown).
Plasma GLP-1 and FGF19 concentrations after gDCA administration. The AUC of GLP-1 was similar between the study days (AUC0-240 -gDCA: 3,110.6 [3,471.7] pmol/L × min vs. +gDCA: 3,232.5 [2,865.8] pmol/L × min; P > 0.05, 2-way RM- ANOVA P > 0.05) (Fig. 2E), whereas the postprandial incremental AUC of the first phase secretion of GLP-1 was higher after gDCA (iAUC0-60: –gDCA: 56.8 [483.8] pmol/L × min vs. +gDCA: 365.7 [388.8] pmol/L × min; P < 0.01) (Fig. 2E).
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