Fig. 2.

Absent compensatory islet hyperplasia in βIRKO/LIRKO mice. (a) Immunostaining of pancreas sections for non-β-cells by using a mixture of antibodies to glucagon, somatostatin, and pancreatic polypeptide as described in Methods. Representative sections from 2- and 6-week-old mice. (Magnification: ×10.) (Scale bar: 50 μm.) (b) β-cell mass at 2 (in micrograms) and 6 (in milligrams) weeks assessed by morphometric analysis as described in Methods. ∗, P < 0.05 LIRKO vs. all other groups. (c) After overnight culture, size-matched islets were incubated in different concentrations of glucose for 45 min. Then the medium was removed and assayed for insulin. Islet insulin content was assayed by acid ethanol extraction as described in Methods. ∗, P < 0.05, 5.5 mM vs. 11 mM glucose; †, P < 0.05, βIRKO/LIRKO or βIRKO vs. control or LIRKO; +, P < 0.05, βIRKO/LIRKO vs. control or βIRKO or LIRKO. (d) Representative pancreas sections from 4-week-old male mice immunostained for insulin by using DAB as a substrate as described in Methods. (Magnification: ×40.) (Scale bar: 50 μm.)