20kDa Human Growth Hormone (20K hGH) Stimulates Insulin-Like Growth Factor-I (IGF-I) Gene Expression at Lower Concentrations than 22K hGH in hGH Receptor-Expressing Ba/F3 Cells

Endocrine Journal

HIDEO YOSHIZATO¹  KUNIO NAKASHIMA¹  YOSHIFUMI HIGASHIMOTO¹  AYAKO SHIMIZU¹  MINORU TANAKA¹  TAKAHIKO FUJIKAWA¹ 

[1] Department of Biochemistry, Faculty of Medicine, Mie University

关键词: 20k hGH;    22K hGH;    IGF-I expression;    GH receptor;   

DOI  :  10.1507/endocrj.47.SupplMarch_S37

学科分类：内分泌与代谢学

来源: Japan Endocrine Society

【 摘 要 】

References(10)Cited-By(3)Growth hormone (GH) secreted from the pituitary is essential for postnatal growth in animals. GH exerts its actions by a direct effect on target organs and by stimulating insulin-like growth factor I (IGF-I) production. In the human pituitary, there is a naturally occurring variant protein which has a molecular mass of 20kDa (20K hGH) besides the major 22kDa hGH (22K hGH), but the physiological actions of 20K hGH are still poorly understood. In this study we have examined its effects on the IGF-I mRNA expression in the pro B-cell line Ba/F3 cells stably expressing hGH receptor (Ba/F3-hGHR). Ba/F3-hGHR cells were incubated for 2h with a series of various concentrations (10pM-10nM) of 20K or 22K hGH. The IGF-I mRNA expression in the Ba/F3-hGHR cells was detected by the RT-PCR method. IGF-I gene expression was increased by 20K and 22K hGH stimulation, but not by PRL or IL-3 in the Ba/F3-hGHR. And this effect was not observed in parental Ba/F3 cells. Lower concentrations of 20K hGH more strongly induced IGF-I gene expression than 22K-hGH. These results suggest that 20K and 22K hGH stimulate the IGF-I gene expression in the Ba/F3-hGHR through hGH receptors, and that the stronger effect of 20K hGH than that of 22K hGH in enhancing the IGF-I gene expression may be correlated with a 20K hGH specific receptor dimerization mechanism.

【 授权许可】

Unknown