L-WRN conditioned medium activates the Wnt/β-catenin signaling pathway.

<p>(A) 100 islets were cultured for 4 days in CMRL-1066 medium containing 10% FBS and 5, 8 or 20 mM glucose or in 50% Wnt3a, R-spondin-3 and Noggin conditioned medium (L-WRN)+Y-27632 and SB-431542 inhibitors. ³H-thymidine was added 24 h before the end of the 4-day period. (B) & (C): islets (150) were treated for 24 h and 72 h, respectively, in CMRL-1066 medium containing 10% FBS and 5 mM glucose ± 5 mM LiCl or in 50% L-WRN ± Y-27632 and SB-431542 inhibitors. Samples were processed for Western blotting and quantitated by Image Lab™ software. pGSK-3β and non-p-β-catenin proteins were normalized to total GSK-3β and total β-catenin proteins, respectively. Data are the means ± SE of n = 3. *<i>P</i><0.05, **<i>P</i><0.01 and ***<i>P</i><0.001 denote significant differences between the treatment condition and the control.