Fig. 8

ITT and OGTT in male DKO, Znt8KO, SstKO, and WT mice. A Blood glucose levels during ITT. A significantly increased blood glucose levels were observed in the HFD-fed DKO mice at 30, 60 and 120 min post the insulin stimulation compared to the WT and Znt8KO mice in the same dietary group (*, p < 0.05). B AUC of blood glucose levels during ITT. The * denotes the significant difference between DKO and WT mice in the HFD groups as indicated (*, p < 0.05). Different letters (a and b) indicate statistical significance between the two dietary groups with the DKO genotype (p < 0.05). C Blood glucose levels during OGTT. DKO mice fed CD had a significantly decreased blood glucose level at 30 min (**, p < 0.01) post the glucose stimulation compared to the WT control. The postprandial glucose levels at 15, 30, 60, and 120 min were all significantly lower in the CD-fed DKO mice than the CD-fed Znt8KO mice (◊, p < 0.05; ◊◊, p < 0.01). D AUC of blood glucose levels during OGTT. A significantly decreased AUC was observed in the CD-fed DKO and SstKO mice compared to Znt8KO mice in the same dietary group (*, p < 0.05). E Plasma insulin levels during OGTT. The * denotes the CD-fed DKO mice had significantly lower plasma insulin levels at the baseline and 15, 30, 60, and 120 min after glucose challenge than the WT control or SstKO (*, p < 0.05; **, p < 0.01; ***, p < 0.001). The letter a implies the significant difference between the Znt8KO and WT or SstKO mice in the CD group (p < 0.05). The letter b shows the significant difference between DKO and Znt8KO mice in the CD groups (p < 0.01). The # denotes the significant difference between DKO and SstKO mice in the HFD groups (p < 0.01). F AUC of plasma insulin levels during OGTT. The * denotes the significant difference between genotypic groups as indicated (*, p < 0.05; **, p < 0.01). Different letters (a and b) indicate statistical significance between the two dietary groups with the DKO genotype (p < 0.05). All data are presented as mean ± S.E., n = 8–10/group. Blood glucose or plasma insulin data was analyzed by a one-way or two-way ANOVA test to compare the means of multiple groups when appropriate followed by a post-hoc test (Tukey’s test). CD, chow diet; HFD, high-fat diet