Improved Expression of Muscle-derived Growth Hormone Releasing Hormone from 慣-Skeletal-muscle Actin Enhancer/Cytomegalovirus Hybrid Enhancer/Promoter |
Xia Gong, Qingyong Meng, Weiwu Jin, Ning Li* |
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Correspondence:
Ning Li, |
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Abstract |
Growth hormone-releasing hormone (GHRH), a hypothalamic neuropeptide can stimulate the growth hormone secretion from the anterior pituitary. In this study, a porcine GHRH expression plasmid pHC-GHRH was used to enhance growth performance through ectopic expressions in muscle tissues of rats. Rats injected with the plasmid of pHC-GHRH and pCMV-GHRH exhibited cumulative weight gains 6.4% and 1% greater than controls. During a 5-day period, significant weight gain differences were observed as follows compared with that of control: during 5-10 days post-injection (DPI) period, the group pHC-GHRH on average 14.5% heavier than controls, 40.73??.88 g vs. 35.57??.23 g (p = 0.0023); during 10-15 DPI period, the group pHC-GHRH on average 13.6% heavier than controls, 37.49??.85 g vs. 33.00??.56 g (p = 0.0146); during 15-20 DPI period, the group pHC-GHRH on average 17.8% heavier than controls, 25.64??.39 g vs. 21.77??.27 g (p<0.05). In addition, plasmids-treated rats maintained higher serum IGF-I than controls. Significant differences of IGF-I were observed on 13 DPI and on 40 DPI in pHC-GHRH group compared with that of controls. This was accomplished through the use of an improved expression cassette that included the cytomegalovirus (CMV) immediate early enhancer/promoter in combination with a 1.5-kilobase portion of porcine ??skeletal muscle actin promoter. |
Keywords:
GHRH; Plasmid DNA; Hybrid Enhancer/Promoter; Growth; Rat; CMV |
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