The effect of combination treatment with trenbolone acetate and estradiol-17β on skeletal muscle expression and plasma concentrations of oxytocin in sheep
The effect of combination treatment with trenbolone acetate and estradiol-17β on skeletal muscle expression and plasma concentrations of oxytocin in sheep
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DOI：
10.1016/j.domaniend.2012.02.004
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发表时间：
2012-07-01
影响因子：
2.1
通讯作者：
Dalrymple, B. P.
中科院分区：
文献类型：
--
作者：
Kongsuwan, K.;Knox, M. R.;Dalrymple, B. P.
醋酸群勃龙（TBA）与雌二醇-17 β（E-2）联合植入可增加牛的生长、饲料转化效率和胴体瘦肉率。我们之前在婆罗门牛中的研究表明，神经肽激素催产素（OXT）可能参与TBA-E-2治疗后增加肌肉生长。本研究旨在确定在TBA-E（2-）植入的雪貂中，背最长肌（LM）中的OXT mRNA表达是否也像在阉牛中发现的那样上调。实时定量PCR用于测量编码OXT前体的基因的表达，这三个基因在TBA-E-2处理的阉牛的LM肌肉中具有增加的表达，MYOD 1（肌肉转录因子），GREB 1（乳腺癌中雌激素的生长调节1）和WISP 2（Wnt-1诱导的信号传导途径蛋白2），和两个基因编码IGF途径蛋白，IGF 1，IGFR，在未处理和TBA-E-2处理的雪貂的LM中。在接受TBA-E-2处理的雪貂中，OXT mRNA的表达增加了约4.4倍（P = 0.01）。TBA-E-2治疗还诱导循环OXT增加2.3倍（P = 0.001）。这些数据，连同观察到未处理的wethers有更高的基线浓度的循环OXT比以前观察到的阉牛，表明，wethers和阉牛有相当不同的OXT激素系统。TBA-E-2处理对IGF 1、IGFR和肌肉调节基因MYOD 1的mRNA水平没有影响（P >= 0.15），但增加了两个生长相关基因GREB 1（P = 0.001）和WISP 2（P = 0.04）的表达。这两个基因都是雌激素和雄激素信号通路的共同基因靶点。因此，它们的作用可能有助于TBA和E-2之间的积极相互作用，对肌肉生长的加性改善。皇冠版权所有（c）2012由爱思唯尔公司发布。All rights reserved.
Implantation of trenbolone acetate (TBA) in conjunction with estradiol-17 beta (E-2) increases growth, feed conversion efficiency, and carcass leanness in cattle. Our previous study in Brahman steers suggested that the neuropeptide hormone oxytocin (OXT) may be involved in increasing muscle growth after TBA-E-2 treatment. The present study aimed to determine whether OXT mRNA expression in the longissimus muscle (LM) is also up-regulated in TBA-E(2-)implanted wethers as has been found in steers. Real-time quantitative PCR was used to measure the expression of the gene encoding the OXT precursor, three genes with increased expression in the LM muscle of TBA-E-2-treated steers, MYOD1 (muscle transcription factor), GREB1 (growth regulation by estrogen in breast cancer 1), and WISP2 (Wnt-1 inducible signaling pathway protein 2), and two genes encoding IGF pathway proteins, IGF1, IGFR, in the LM of both untreated and TBA-E-2-treated wethers. The expression of OXT mRNA in wethers that received the TBA-E-2 treatment was increased similar to 4.4-fold (P = 0.01). TBA-E-2 treatment also induced a 2.3-fold increase in circulating OXT (P = 0.001). These data, together with the observation that untreated wethers had much higher baseline concentrations of circulating OXT than previously observed in steers, suggest that wethers and steers have quite different OXT hormone systems. TBA-E-2 treatment had no effect on the expression of IGF1, IGFR, and the muscle regulatory gene MYOD1 mRNA levels in wethers (P >= 0.15), but there was an increase in the expression of the two growth-related genes, GREB1 (P = 0.001) and WISP2 (P = 0.04). Both genes are common gene targets for both the estrogen and androgen signaling pathways. Consequently, their actions may contribute to the positive interaction between TBA and E-2 on additive improvements on muscle growth. Crown Copyright (c) 2012 Published by Elsevier Inc. All rights reserved.