Figure 4.

Glucose tolerance tests for Y1-R^+/+ and Y1-R^−/− mice at 31 weeks of age. Half of wild-type (three males and five females) and deficient (four males and five females) mice (29 weeks of age) were given a 30% glucose solution instead of plain water for 2 weeks. Insulin (A) and glucose (B) levels with or without the administration of 30% glucose, respectively (∗, P < 0.05). (C) The effect of the administered glucose on insulin secretion. The ratio of plasma insulin level (A) to blood glucose level (B) (insulin/glucose ratio) was estimated to determine the capability of insulin secretion in response to glucose administration. All values are means ± SE. A two-tailed unpaired Student’s t test was used for statistical analysis.