Fed plasma insulin (a), insulin-tolerance test (b), and pancreatic islet cell histology (c and d) in male control animals. Plasma insulin was approximately tenfold higher (P < 0.001) in MCH-transgenic mice, which showed insulin resistance on insulin-tolerance testing (P < 0.001, repeated measures ANOVA). Representative sections of pancreas showed that when compared with control animals (c), MCH-transgenic mice had a twofold increase in islet size (d) (P < 0.02).