Control (filled squares) and mutant mice (filled circles) were subjected to either an oral (A, OGTT) or intraperitoneal (B, IPGTT) glucose challenge or an ITT. Blood glucose levels were then measured at the indicated time points. (A) In the OGTT, mutant mice show a slightly improved glucose clearance from the blood. (B) In the IPGTT, at all time points measured, blood glucose levels of mutant mice do not rise to the same levels as in control mice. (C) The ITT clearly shows an improved insulin sensitivity of mutant compared with control mice. n = 6–7, for control and mutant mice. “0” indicates the blood glucose level before the glucose challenge. *P < 0.05, **P < 0.01, ***P < 0.001. The age of the mice analyzed is 7–10 weeks.