D'Ercole A J, Stiles A D, Underwood L E
Proc Natl Acad Sci U S A. 1984 Feb;81(3):935-9. doi: 10.1073/pnas.81.3.935.
We have validated a method for extracting and measuring the tissue content of somatomedin C (Sm-C)/insulin-like growth factor I (IGF-I), a growth-hormone-dependent, growth-promoting peptide. The Sm-C content of tissue extracts was strongly growth-hormone dependent because most of the tissues studied from hypophysectomized rats contained significantly less Sm-C than normal tissues. The intraperitoneal administration of ovine growth hormone (oGH) to hypophysectomized rats caused tissue extractable Sm-C to increase in kidney, liver, lung, heart, and testes. Tissue Sm-C responses to oGH were maximal after 12 hr, 6 hr before the maximal increment in serum. In liver and lung, the tissue Sm-C response to various doses of oGH fit linear regression models, and the doses of oGH needed to increase the Sm-C are in the range of those required to increase protein synthesis. Although these results do not exclude the possibility that the somatomedins act by hormone-like endocrine mechanisms, they add support to the concept that these peptides act through autocrine or paracrine mechanisms, being produced at multiple sites and acting at or near their sites of production.
我们已经验证了一种提取和测量生长调节素C（Sm-C）/胰岛素样生长因子I（IGF-I）组织含量的方法，Sm-C/IGF-I是一种依赖生长激素的促生长肽。组织提取物中的Sm-C含量强烈依赖于生长激素，因为从垂体切除大鼠身上研究的大多数组织所含的Sm-C明显少于正常组织。给垂体切除大鼠腹腔注射羊生长激素（oGH）会使肾脏、肝脏、肺、心脏和睾丸中可提取的组织Sm-C增加。组织Sm-C对oGH的反应在12小时后达到最大值，比血清中最大增量提前6小时。在肝脏和肺中，组织Sm-C对不同剂量oGH的反应符合线性回归模型，增加Sm-C所需的oGH剂量与增加蛋白质合成所需的剂量范围相同。尽管这些结果并不排除生长调节素通过类似激素的内分泌机制起作用的可能性，但它们支持了这些肽通过自分泌或旁分泌机制起作用的概念，即在多个部位产生并在其产生部位或附近起作用。
