Page 134 - Human Bile Acid Metabolism: a Postprandial Perspective

Chapter 7
Figure 3. Postprandial plasma bile acids: conjugates.
Lean subjects (open symbols) and obese patients with type 2 diabetes (closed symbols) were provided with equicaloric meals at ZT 0:30, 6:00 and 11:30 (dotted lines). A glycine conjugated B taurine conjugated and C unconjugated bile acid excursions. Data are change versus baseline (ZT 0:15) expressed as means ± SEM. Zeitgeber Time 0 represents the time of lights on.
from breakfast to lunch and no change from lunch to dinner, whereas the healthy controls showed an increase in plasma glucose iAUC from breakfast to lunch and a further increase to dinner. Plasma insulin iAUC values showed no significant rhythm over the day in either of the groups (Fig. 1).
Fasting total BA levels and fasting BA subtype levels were not different between healthy subjects and obese patients with type 2 diabetes (Table 1). We observed clear postprandial peaks of total plasma BAs and the individual BA subtypes CA, CDCA, DCA after all three meals. The major constituent of the postprandial BA response was CDCA (Fig. 2). Glycine-conjugated forms peaked in both obese patients with type 2 diabetes and healthy subjects, whereas taurine-conjugated and unconjugated BA peaks were less noticeable. Most BAs appeared in plasma in their glycine-conjugated form (Fig. 3).
Meal time did not affect postprandial AUCs of either total BAs, any individual BA subtype or the distribution of conjugated vs unconjugated BAs (Fig. 2 and 3, Table 2). AUCs did not differ between the obese type 2 diabetes patients and healthy subjects. However, postprandial peak times were earlier for total BAs, CDCA, and glycine conjugates in the obese patients with type 2 diabetes compared to healthy subjects (Fig. 2 and 3, Table 3, group effect on peak time P<0.05). Meal time did not affect peak times (Table 2).
ABC
8 6 4 2 0
22
00
0 4 8 12 16
Zeitgeber 􏰀ime (hr)
0 4 8 12 16
Zeitgeber 􏰀ime (hr)
0 4 8 12 16
Zeitgeber 􏰀ime (hr)
132
D 􏰁l􏰂􏰃i􏰄e 􏰃o􏰄􏰅􏰆gate􏰇 (μmol/L)
D 􏰀a􏰆ri􏰄e 􏰃o􏰄􏰅􏰆gate􏰇 (μmol/L)
D U􏰄􏰃o􏰄􏰅􏰆gate􏰈 BA (μmol/L)