Figure 7. Exogenous ghrelin deteriorates glucose tolerance via β-cell GHSR.

(A) When ghrelin at 10 nmol/kg was i.p. injected simultaneously with 2 g/kg glucose, the blood glucose levels were higher in comparison to saline-injected control values. (B) In GHSR-null mice, i.p. injection of ghrelin failed to affect blood glucose responses during GTT. (C) In GHSR-null/Ins-Cre mice, i.p. injection of ghrelin significantly elevated the blood glucose increases in GTT. (D) The profiles of blood glucose levels during insulin tolerance tests (ITT) and (E) the HOMA-IR index exhibited little differences between GHSR-null, GHSR-null/Ins-Cre and wild-type mice, suggesting that insulin sensitivity was not significantly altered. n = 7. *P < 0.05.