FIG. 6.

Leu induces HIF-1α, a repressor of β-cell differentiation. A: Representative immunoblot for HIF-1α expression in protein lysates from E13.5 pancreatic buds that were treated with Leu for 1 or 7 days. Immunoblot for phospho (P)-rpS6 indicates that Leu treatment induced mTOR activity. B: Representative immunoblot for HIF-1α in protein lysates from E13.5 pancreatic buds that were treated for 24 h with rapamycin (Rapa), Leu, or Leu and rapamycin. Immunoblot for P-rpS6 indicates that Leu treatment induced mTOR activity. The quantified results are presented in (C). D: Real-time PCR quantification of two HIF-1α target genes. Glut1 and Redd1 mRNA in pancreata after 0, 1, 3, 5, and 7 days in culture without Leu (white bars), with rapamycin (gray bars), with Leu (black bars), or with both rapamycin and Leu (dashed bars). Data are mean ± SEM of at least three independent experiments. *P < 0.05. (A high-quality color representation of this figure is available in the online issue.)