Takizawa T, Arishima K, Yamamoto M, Shirai M, Somiya H, Eguchi Y
Department of Developmental Biotechnology, Azabu University School of Veterinary Medicine, Kanagawa, Japan.
J Vet Med Sci. 1993 Jun;55(3):379-81. doi: 10.1292/jvms.55.379.
This work was conducted to know whether thyroxine (T4) when injected into fetal rats would induce a constriction of the ductus arteriosus (DA). In Experiment 1, fetal rats on day 20 of gestation were given a subcutaneous injection of 1 or 10 micrograms T4 through the maternal uterine wall, and were autopsied 3 or 6 hr later. Similarly, in Experiment 2, the mother rats were given an injection of hydrocortisone (10 mg/kg) just after fetal T4 injections. In either series of experiments, uninjected littermates served as controls. According to the whole-body freezing and shaving method, the DA was exposed and calibrated under a dissecting microscope. In Experiment 1, the DAs of the T4-injected fetuses, 3 hr later, were significantly smaller in caliber than those of their controls, but recovered 6 hr later. In Experiment 2 with fetal T4 injection followed by maternal hydrocortisone injection, the DAs of the T4-injected fetuses were further smaller in caliber than those of their controls which were clearly shrunken as compared with those of controls in Experiment 1. These results indicate that T4 exerts a constrictive effect on the DA, an effect which is strengthened in the presence of hydrocortisone.
本研究旨在了解向胎鼠注射甲状腺素（T4）是否会导致动脉导管（DA）收缩。在实验1中，对妊娠第20天的胎鼠通过母体子宫壁进行皮下注射1或10微克T4，并在3或6小时后进行解剖。同样，在实验2中，在给胎鼠注射T4后立即给母鼠注射氢化可的松（10毫克/千克）。在这两个系列实验中，未注射的同窝仔鼠作为对照。根据全身冷冻和刮毛方法，在解剖显微镜下暴露并测量DA。在实验1中，注射T4的胎鼠在3小时后的DA管径明显小于其对照组，但在6小时后恢复。在实验2中，先给胎鼠注射T4，然后给母鼠注射氢化可的松，注射T4的胎鼠的DA管径比其对照组更小，与实验1中的对照组相比，实验2中的对照组明显收缩。这些结果表明，T4对DA有收缩作用，在氢化可的松存在的情况下这种作用会增强。
