Fig 2: GLP-2 action on collagen maturity is dependent on adenylyl cyclase activity. MC3T3-E1 osteoblast cells were incubated with a specific adenylyl cyclase inhibitor (DDA) prior to incubation with 50 pM [Gly²]-GLP-2. (A) cAMP, (B) LOX activity, and (C) collagen maturity in osteoblast cultures. **p < 0.01 vs. vehicle-treated cultures.

Fig 3: Expression and activation of proglucagon-derived peptide receptors in murine osteoblasts. (A) Relative expression of glucagon receptor (Gcgr), glucagon-like peptide-1 receptor (Glp1r), and glucagon-like peptide-2 receptor (Glp2r) was investigated by qPCR. CHO-K1 cells transfected with the empty pcDNA3.1 vector was used as negative control. CHO-K1 cells transfected with the pcDNA 3.1 vector encoding the Gcgr, Glp1r, or Glp2r sequence were used as positive control. Expression in MC3T3-E1 cells was used to assess expression in osteoblast cells. (B) Presence of GCGr, GLP-1r, and GLP-2r was determined by Western blot with commercially available antibodies. Arrowheads point out at the theoretical location of receptor. (C) Intracellular levels of cAMP were determined in MC3T3-E1 cells 45 min after treatment with 50 pM of GCG, [D-Ala²]-GLP-1, or [Gly²]-GLP-2. (D) Phospho-proteome array in MC3T3-E1 cells treated with either saline or 50 pM of GLP-2 or its long-lasting analog [Gly²]-GLP-2. (E) Intracellular levels of cAMP were determined in MC3T3-E1 cells 45 min after treatment with 50 pM of GLP-2 or [Gly²]-GLP-2. *p < 0.05 and **p < 0.01 vs. saline-treated cultures.