Kapitola J, Zák J
Laborator pro endokrinologii a metabolismus, III. interní klinika, 1. lékarské fakulty Univerzity Karlovy, U Nemocnice 1, 128 08 Praha 2, Czech Republic.
Sb Lek. 2003;104(2):133-7.
Parathyroid hormone (PTH)--besides its main osteotrophic action--exerts also vascular effect demonstrated formerly also in bones. The aim of the presented work was to verify this effect of PTH using the radioactive microsphere method and to ascertain simultaneously whether NO does participate or not in this effect of PTH. We performed two experiments which were arranged in the same way, as follows: group I--controls, group II--PTH, group III--L-NAME, group IV--L-NAME + PTH. Parathyroid hormone 1.34 fragment (Sigma, USA) was administered to each animal 6-12 minutes before the injection of radioactive microspheres in the dose of 3 micrograms in the experiment A, 10 micrograms in the experiment B. NG-nitro-L-arginin methyl ester (Sigma, USA) was given in the food for ten days before the experiment in the concentration of 0.025% in experiment A, 0.05% in experiment B.
We present the results of experiment A in the part "Results" of the paper briefly in percentages--they are similar to the results of experiment B, but without statistical significance. Administration of PTH increased statistically significantly the microsphere uptake in tibia and distal femur and also the blood flow in both bones, increased the cardiac output and lowered blood pressure. Administration of L-NAME alone induced decrease of the heart rate only. After the injection of PTH to the rats fed L-NAME there was--compared to the injection of PTH only--the blood flow through both bones significantly lower. The observed increase in the bone blood flow as well as changes in the general circulation show that i.v. injection of PTH under the experimental conditions used does induce vasodilatation in female rats. Influence of these changes by the administration of L-NAME indicates possible participation of the nitric oxide (NO) in the observed effect of PTH on the vessles.
甲状旁腺激素（PTH）——除了其主要的骨营养作用外——还具有血管效应，此前在骨骼中也已得到证实。本研究的目的是使用放射性微球法验证PTH的这种效应，并同时确定一氧化氮（NO）是否参与PTH的这一效应。我们进行了两个实验，实验设置如下：第一组——对照组，第二组——PTH组，第三组——L - 精氨酸甲酯（L - NAME）组，第四组——L - NAME + PTH组。在实验A中，于注射放射性微球前6 - 12分钟给每只动物注射1.34片段的甲状旁腺激素（美国Sigma公司），剂量为3微克；在实验B中剂量为10微克。在实验前10天，以0.025%的浓度（实验A）和0.05%的浓度（实验B）将NG - 硝基 - L - 精氨酸甲酯（美国Sigma公司）添加到食物中。
我们在论文“结果”部分简要以百分比形式呈现了实验A的结果——它们与实验B的结果相似，但无统计学意义。注射PTH后，胫骨和股骨远端的微球摄取量以及两根骨头的血流量在统计学上显著增加，心输出量增加，血压降低。单独注射L - NAME仅导致心率下降。与仅注射PTH相比，给喂食L - NAME的大鼠注射PTH后，两根骨头的血流量显著降低。观察到的骨血流量增加以及全身循环的变化表明，在所使用的实验条件下静脉注射PTH确实可诱导雌性大鼠血管舒张。L - NAME给药对这些变化的影响表明一氧化氮（NO）可能参与了观察到的PTH对血管的作用。
