Abstract

Animals are frequently exposed to various kinds of environmental stressors and estrogen is known to play important role in stress response besides its crucial role in regulation of cellular proliferation, metabolic activity and reproduction. The study investigates the estrogen antagonist, tamoxifen (TM), mediated estrogen receptor alpha (ERα) expression, to modulate stress induced parameters in chickens. The study further explores the activity of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPX) and malonaldehyde (MDA) in brain, ovary and shell gland during water deprivation (WD) and tamoxifen administration in sexually mature chicken. WD and TM administration both decrease the plasma estradiol while WD increases corticosterone. WD also elevates MDA concentration in the brain, ovary and shell gland while TM lowers it. WD and TM administration lowers the specific activity of SOD in brain and shell gland. In contrast, WD increases the specific activity of catalase, GPx and GR in the brain and shell gland, while TM decreases it. It appears that endogenous estradiol plays a crucial role in expression of antioxidant enzymes and tamoxifen acts as an antioxidant by reducing the oxidative stress in chicken. Abundant expression of ERα has been observed in the shell gland of egg laying birds while stress like water deprivation and TM down-regulates its expression. Thus, it can be concluded that expression of ERα in shell gland plays a predominant role in mediating estrogen action in response to water deprivation stress and tamoxifen.

摘要

动物经常暴露于各种环境应激源，雌激素除了在调节细胞增殖，代谢活性和繁殖中起关键作用外，在应激反应中也起着重要作用。该研究调查了雌激素拮抗剂他莫昔芬（TMA）介导的雌激素受体α（ERα）表达，以调节鸡的应激诱导参数。该研究进一步探讨了性成熟鸡在缺水（WD）和他莫昔芬给药期间脑，卵巢和壳腺中超氧化物歧化酶（SOD），过氧化氢酶和谷胱甘肽过氧化物酶（GPX）和丙二醛（MDA）的活性。WD和TM给药均降低血浆雌二醇，而WD增加皮质酮。WD还可以提高大脑，卵巢和壳腺中的MDA浓度，而TM则可以降低它。WD和TM给药可降低脑和壳腺中SOD的比活性。相反，WD增加过氧化氢酶，GPx和GR在脑和壳腺中的比活性，而TM则降低它。看来内源性雌二醇在抗氧化酶的表达中起着至关重要的作用，而他莫昔芬通过降低鸡的氧化应激而起抗氧化剂的作用。在产蛋鸟类的壳腺中观察到了ERα的大量表达，而诸如缺水和TM的压力下调了ERα的表达。因此，可以得出结论，ERα在壳腺中的表达在响应缺水应激和他莫昔芬而介导雌激素作用中起主要作用。脑和壳腺中的GPx和GR，而TM则降低。看来内源性雌二醇在抗氧化酶的表达中起着至关重要的作用，而他莫昔芬通过降低鸡的氧化应激而起抗氧化剂的作用。在产蛋鸟类的壳腺中观察到了ERα的大量表达，而诸如缺水和TM的压力下调了ERα的表达。因此，可以得出结论，ERα在壳腺中的表达在响应缺水应激和他莫昔芬而介导雌激素作用中起主要作用。脑和壳腺中的GPx和GR，而TM则降低。看来内源性雌二醇在抗氧化酶的表达中起着至关重要的作用，他莫昔芬通过降低鸡的氧化应激而起抗氧化剂的作用。在产蛋鸟类的壳腺中观察到了ERα的大量表达，而诸如缺水和TM的应激则下调了它的表达。因此，可以得出结论，ERα在壳腺中的表达在响应缺水应激和他莫昔芬而介导雌激素作用中起主要作用。在产蛋鸟类的壳腺中观察到了ERα的大量表达，而诸如缺水和TM的压力下调了ERα的表达。因此，可以得出结论，ERα在壳腺中的表达在响应缺水应激和他莫昔芬而介导雌激素作用中起主要作用。在产蛋鸟类的壳腺中观察到了ERα的大量表达，而诸如缺水和TM的压力下调了ERα的表达。因此，可以得出结论，ERα在壳腺中的表达在响应缺水应激和他莫昔芬而介导雌激素作用中起主要作用。