EFFECT OF GROWTH-HORMONE ON THE TRANSLOCATION OF GLUT4 AND ITS RELATION TO INSULIN-LIKE AND ANTIINSULIN ACTION

Citation
I. Yokota et al., EFFECT OF GROWTH-HORMONE ON THE TRANSLOCATION OF GLUT4 AND ITS RELATION TO INSULIN-LIKE AND ANTIINSULIN ACTION, Biochimica et biophysica acta. Molecular cell research, 1404(3), 1998, pp. 451-456
Citations number
21
Categorie Soggetti
Biology,Biophysics
ISSN journal
01674889
Volume
1404
Issue
3
Year of publication
1998
Pages
451 - 456
Database
ISI
SICI code
0167-4889(1998)1404:3<451:EOGOTT>2.0.ZU;2-4
Abstract
To elucidate the effect of growth hormone (GH) on the insulin signal t ransduction pathway leading to the translocation of glucose transporte r-4 (GLUT4), we constructed Chinese hamster ovary cells that overexpre ssed GH receptor and GLUT4. Treatment with GH triggered GLUT4 transloc ation, and this translocation was completely inhibited by wortmannin. GH-induced GLUT4 translocation reached a maximum level after 30 min, a nd then gradually decreased and returned to the basal level after 2 h. Tyrosine phosphorylation of JAK2 also became maximal after 30 min and then gradually decreased. In contrast, GLUT4 translocation remained u nchanged for 2 h after insulin treatment, and tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) also remained constant for up to 2 h. Chronic GH treatment had almost no effect on insulin-stimulat ed Akt kinase activation and GLUT4 translocation. These results sugges t that GH and insulin translocate GLUT4 in a similar manner, at least in part, and the difference in translocation depends on the difference in the tyrosine phosphorylation of JAK2 and IRS-1. The anti-insulin a ction of GH after chronic GH treatment does not appear to be mainly du e to the inhibition of GLUT4 translocation. 0167-4889/98/$ - see front matter (C) 1998 Elsevier Science B.V. All rights reserved.