Possible Involvement of Phosphatidylinositol 3-Kinase/Akt Pathway in Insulin-like Growth Factor-I-induced Alkaline Phosphatase Activity in Osteoblasts

T. Noda; H. Tokuda; M. Yoshida; E. Yasuda; Y. Hanai; S. Takai; O. Kozawa

doi:10.1055/s-2005-861468

Hormone and Metabolic Research, Table of Contents

Horm Metab Res 2005; 37(5): 270-274
DOI: 10.1055/s-2005-861468

Original Basic

Possible Involvement of Phosphatidylinositol 3-Kinase/Akt Pathway in Insulin-like Growth Factor-I-induced Alkaline Phosphatase Activity in Osteoblasts

T. Noda¹ , H. Tokuda^1, ² , M. Yoshida¹ , E. Yasuda¹ , Y. Hanai² , S. Takai¹ , O. Kozawa¹

¹ Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Japan
² Department of Clinical Laboratory, National Hospital for Geriatric Medicine, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan

Abstract

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.

Key words

IGF-I - Alkaline phosphatase - Akt - Osteoblast

Full Text

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Dr. Osamu Kozawa

Department of Pharmacology, Gifu University Graduate School of Medicine ·

Gifu 501-1194 · Japan

Phone: + 81 (58) 230 62 14

Fax: + 81 (58) 230 62 15

Email: okozawa@cc.gifu-u.ac.jp