HORMONES AND AGING--PITUITARY-HYPOTHALAMIC FUNCTION IN EXPERIMENTAL ANIMALS

激素与衰老--实验动物的垂体-下丘脑功能

• 批准号: 3767750
• 负责人: S MITCHELL HARMAN
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3767750
• 关键词: G protein; RNase protection assay; aging; biological signal transduction; genetic transcription; glycolysis; growth factor receptors; hormone regulation /control mechanism; insulinlike growth factor; laboratory mouse; messenger RNA; molecular cloning; northern blottings; nuclear runoff assay; pituitary gland; polymerase chain reaction; somatotropin; testosterone; translation factor; western blottings

In an investigation of the effects of age on tissue responses to hormones, young and old male mice were treated with rhGH, T, GH plus T, or placebo and mRNA extracts were prepared from various tissues and probed by Northern blotting, RNA'ase protection assay, or template specific quantitative PCR to quantify specific mRNA's for IGF-I,IGF-I receptor, IGF-I binding proteins 1 and 3, and elongation factor l-alpha as well as tissue specific differentiation factors and structural proteins (e.g. in muscle, myogenin and alpha-myosin heavy chain; in bone alpha- 1 procollagen). Pretreatment, IGF-I levels were significantly lower in old mice, and plasma T and the ratio of EF-1alpha/18S mRNA were reduced, but not significantly so. After rhGH treatment, IGF-I levels tended to increase, but this was significant only in old mice after 5 days. After 10 days, treatment with rhGH alone increased the ratio of EF-1alpha/18SmRNA similarly in mature and old mice, whereas treatment with T alone increased EF-1alpha/18S mRNA only in old mice. Combination treatment with rhGH + T increased EF-1alpha/l8S mRNA significantly after 5days in mature mice. These data suggest that, in male mice, EF-1alpha gene expression can be increased by GH or T, but with no additive response to GH + T. Aging appears to affect the pattern of this response. Continuation of this work should include estimation of IGF-I and IGF-I receptor protein by Western blotting and nuclear run-off assays to establish whether the increases observed in EF-1alpha represent regulation at the transcriptional level.

在一项关于年龄对组织对激素反应的影响的研究中， 用rhGH、T、GH + T或安慰剂处理年轻和年老雄性小鼠 从各种组织中制备mRNA提取物，并通过 北方印迹、RNA酶保护测定或模板特异性 定量PCR以定量IGF-I，IGF-I受体， IGF-I结合蛋白1和3、延伸因子1-α以及 组织特异性分化因子和结构蛋白（例如， 肌肉、肌细胞生成素和α-肌球蛋白重链;骨中α- 1 前胶原）。治疗前，IGF-I水平明显低于老年人， 血浆T和EF-1 α/18 S mRNA比值降低， 并不显著。rhGH治疗后，IGF-I水平趋于 增加，但这仅在5天后的老年小鼠中显著。经过10 单独用rhGH处理3d后，EF-1 α/18 SmRNA比值增加， 在成熟和老年小鼠中也是如此，而单独用T治疗增加了 EF-1 α/18 S mRNA仅在老年小鼠中表达。rhGH + T联合治疗 成熟小鼠5d后EF-1 α/18 S mRNA表达显著增加。 这些数据表明，在雄性小鼠中，EF-1 α基因的表达可以被抑制。 GH或T增加，但对GH + T无加性反应。老化 似乎影响了这种反应的模式。继续开展这项工作 应包括通过Western blot估计IGF-I和IGF-I受体蛋白 印迹和核径流分析，以确定是否增加 在EF-1 α中观察到的表达代表了转录水平上的调节。