FIG. 1.

Anthropometric measurements and metabolic phenotype of the C57Bl6/J/STAT4^−/− mice and wild-type controls. A: Body weight, perigonadal adiposity, obesity index, and feed efficiency were significantly increased in both the wild-type and knockout female mice after 16 weeks on an HFD; mice were fed either a 60 kcal% fat HFD for 16 weeks, starting at 10 weeks of age (n = 12–16) or were kept on chow (n = 7–8); the results for the HFD mice are combined from two different but similar experiments (experiments 1 and 2). The obesity index was calculated by dividing the cubic root of the body weight (in grams) by the naso-anal length (in millimeters) × 10⁴. Feed efficiency was calculated by dividing the weight gain by food intake in the last week on high-fat or chow diets (week 16); the results are from six to eight mice per group and represent data from experiment 1. *Significant compared with the chow-fed group. B: Intraperitoneal GTTs and ITTs were performed after 16 weeks of HFD or chow feeding. The AUC was measured in each case. Plotted values in the histograms are the average ± SEM from 7–16 mice per group. *Significant compared with STAT4^−/− mice. C: In vitro glucose-stimulated insulin secretion was measured in pancreatic islets of C57Bl6/J/STAT4^−/− mice and wild-type controls isolated after 16 weeks on an HFD. Islets were cultured overnight and subsequently treated for 1 h with 3 or 18 mmol/L glucose. Insulin was measured by ELISA in the media of the islets stimulated with a low- or high-glucose concentration. Results represent average ± SEM from sixmice per group; the null hypothesis was rejected for P < 0.05. HF, high fat.