Figure 1: Bbs4−/− mice manifest impaired glucose handling in the absence of morphological abnormalities in the pancreas.

(a,b) Representative examples of Bbs4−/− (a) and littermate control (b) islets (n=3). Insulin is shown in green, glucagon in red, the nuclei are counterstained with 4,6-diamidino-2-phenylindole (DAPI; blue). Scale bars, 20 μm. (c) Islet size distribution is slightly skewed towards larger islets in 4-week-old male Bbs4−/− mice without clear differences in range (n=4). The red line demarks the median, the boxes the range from 25th to 75th percentile, the bars 10th and 90th percentile and the dots the 5th and 95th percentile of the size distribution. (d) Serum insulin levels are not significantly different between wt and Bbs4−/− mice (4 weeks, male, n=4, error bars: standard deviation, st. dev.). (e) Total pancreatic insulin content is not statistically different between 7- and 9-week-old Bbs4−/− mice and littermate controls (n=4). (f) Glucose handling is significantly impaired in Bbs4−/− mice (red) compared with littermate controls (black; n=5, 7–9 weeks; t=80 min, *P=0.0496 (t-test)). Error bars represent standard error, s.e.m. (g) At the age of glucose tolerance testing, Bbs4−/− and littermate controls have similar body weight. The boxes represent the 5th to 95th percentile and the red lines depict the median.