Possible involvement of phosphatidylinositol 3-kinase/Akt pathway in insulin-like growth factor-I-induced alkaline phosphatase activity in osteoblasts

• Published in: Hormone and metabolic research Vol. 37; no. 5; p. 270
• Main Authors: Noda, T, Tokuda, H, Yoshida, M, Yasuda, E, Hanai, Y, Takai, S, Kozawa, O
• Format: Journal Article
• Language: English
• Published: Germany 01.05.2005
• Subjects: Alkaline Phosphatase - biosynthesis; Animals; Clone Cells; Insulin-Like Growth Factor I - pharmacology; Mice; Osteoblasts - enzymology; Phosphatidylinositol 3-Kinases - metabolism; Protein-Serine-Threonine Kinases - metabolism; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-akt; Signal Transduction - drug effects; Signal Transduction - physiology
• ISSN: 0018-5043
• DOI: 10.1055/s-2005-861468

In the present study, we investigated whether Akt is involved in insulin-like growth factor-I (IGF-I)-stimulated activity of alkaline phosphatase, a marker of mature osteoblast phenotype, in osteoblast-like MC3T3-E1 cells. IGF-I induced the phosphorylation of Akt in these cells. Akt inhibitor significantly suppressed the IGF-I-stimulated alkaline phosphatase activity. The phosphorylation of Akt induced by IGF-I was reduced by the Akt inhibitor. LY294002 and wortmannin, inhibitors of phosphatidylinositol 3-kinase, significantly suppressed the IGF-I-induced alkaline phosphatase activity. The phosphorylation of Akt induced by IGF-I was markedly reduced by LY294002 and wortmannin. These results strongly suggest that phosphatidylinositol 3-kinase/Akt plays a role in the IGF-I-stimulated alkaline phosphatase activity in osteoblasts.