Growth Hormone and Insulin-Like Growth Factor Ⅰ: Effects on mRNA Expression Levels of Key Kinases and Regulatory Factors Regulating Milk Protein Synthesis

JI Yun; PANG Xueyan; TIAN Qing; WANG Mengzhi; WANG Hongrong; AO Changjin

doi:10.3969/j.issn.1006-267x.2013.01.025

2013 , Vol. 25 >Issue 1: 198 - 207

DOI: https://doi.org/10.3969/j.issn.1006-267x.2013.01.025

Short Communications

Growth Hormone and Insulin-Like Growth Factor Ⅰ: Effects on mRNA Expression Levels of Key Kinases and Regulatory Factors Regulating Milk Protein Synthesis

JI Yun ,
PANG Xueyan ,
TIAN Qing ,
WANG Mengzhi ,
WANG Hongrong ,
AO Changjin

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1. College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China;
2. College of Animal Science, Inner Mongolia Agricultural University, Huhhot 010018, China

Received date: 2012-07-16

Online published: 2013-01-04

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Abstract

This experiment was conducted to investigate the effects of growth hormone (GH) and insulin-like growth factor Ⅰ (IGF-Ⅰ) on mRNA expression levels of key kinases and regulatory factors regulating milk protein synthesis in cultured bovine mammary epithelial cells in vitro. Four treatments were employed to culture the purified mammary epithelial cells of a Holstein dairy cow and growth medium without serum was used in a control group, and based on the control group, mediums supplemented with GH (100 ng/mL), IGF-Ⅰ (100 ng/mL) and GH (100 ng/mL)+IGF-Ⅰ (100 ng/mL) were used in experimental groups. After cultured for 24 h, the mRNA expression levels of CSN3, key kinases and regulatory factors regulating milk protein synthesis, GHR and IGF-ⅠR were determined by real-time quantitative PCR (RT-qPCR). The results showed as follows: there were mRNA expressions of GHR and IGF-ⅠR in mammary epithelial cells cultured in vitro, and CSN3 mRNA expression level was significantly enhanced in all experimental groups (P<0.05), however, no cumulative effect was found; compared with the control group, the mRNA expression level of E74-like transcription factor 5 (ELF5) tended to be increased in GH group (P<0.10), mRNA expression levels of mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase 1 (rpS6K1) were significantly increased in IGF-Ⅰ group (P<0.05), but on augmented effect was found in GH+IGF-Ⅰ group. All results indicate that GH and IGF-Ⅰ may modulate κ-casein synthesis independently through affecting mRNA expressions of key kinases and regulatory factors that regulating milk protein synthesis.

Key words： growth hormone; insulin-like growth factor Ⅰ; mammary epithelial cell; milk protein; mRNA expression level

Cite this article

JI Yun , PANG Xueyan , TIAN Qing , WANG Mengzhi , WANG Hongrong , AO Changjin . Growth Hormone and Insulin-Like Growth Factor Ⅰ: Effects on mRNA Expression Levels of Key Kinases and Regulatory Factors Regulating Milk Protein Synthesis[J]. Chinese Journal of Animal Nutrition, 2013 , 25(1) : 198 -207 . DOI: 10.3969/j.issn.1006-267x.2013.01.025

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