藏羚羊和藏系绵羊血液内分泌激素水平的比较研究

Comparisons of endocrine hormones levels between Tibetan antelope and Tibetan sheep

为了探讨藏羚羊适应高原环境的内分泌系统的功能特点,我们对藏羚羊(9只)和藏系绵羊(10只)进行了内分泌激素水平的比较。在海拔4300m地区捕获到动物后,随即运至海拔2800m实验基地,次日早晨抽取右侧颈静脉血,采用放射免疫法(radioimmunoassay,RIA)或酶联免疫吸附实验法(enzyme-linked immunosorbent assay,ELISA)测定下丘脑-腺垂体-外周腺轴20项内分泌激素水平,用导管插入术记录动物心率(heart rate,HR)、收缩压(systolic blood pressure,SBP)、舒张压(diastolic bloodpressure,DBP)和平均肺动脉压(mean pulmonary arterial pressure,mPAP)。使用血细胞分析仪测定血红蛋白(hemoglobin,Hb)含量。结果显示,藏羚羊血液中FT3、FT4、AngⅡ水平显著低于藏系绵羊,而藏羚羊血液中TRH、CRH、F、GHRH、E2、Ald、ACTH、CGRP水平则显著高于藏系绵羊。相对于藏系绵羊,藏羚羊HR、mPAP、SBP、DBP和Hb含量明显较低。藏羚羊和藏系绵羊的Hb、AngⅡ水平均与各自mPAP呈中度正线性相关;另外,藏羚羊的FT3与GH呈中度正线性相关、与ACTH呈中度负线性相关。以上这些结果提示,藏羚羊内分泌系统的生物学特征是低代谢高应激,这为进一步揭示藏羚羊的低氧适应机制提供了实验依据。

The Tibetan antelope, a prototype mammal, has developed a unique adaptation to extreme high altitude-associated hypoxia. To investigate the role of the endocrine system in adaptation to high altitude in the Tibetan antelope, comparisons of endocrine hormones levels between Tibetan antelope （n = 9） and Tibetan sheep （n = 10） were performed. Both two kinds of animals were captured at an altitude of 4 300 m and then transported to experimental base at 2 800 m altitude. The blood samples were drawn from right external jugular vein in the next morning, and the 20 hormones in hypothalamus-adenohypophysis-peripheral hormonal axis were measured with radioimmunoassay or enzyme-linked immunosorbent assay. Heart rate （HR）, systolic blood pressure （SBP）, diastolic blood pressure （DBP） and mean pulmonary arterial pressure （mPAP） were recorded using catheterization. Moreover, hemoglobin （Hb） content was measured by blood analyser. The results showed that, the levels of FT 3 , FT 4 and Ang II in Tibetan antelope were significantly lower than those in Tibetan sheep, whereas TRH, CRH, GHRH, F, E 2 , Ald, ACTH and CGRP levels were significantly greater in Tibetan antelope than those in the Tibetan sheep. Compared with Tibetan sheep, Tibetan antelope showed lower HR, mPAP, SBP, DBP and Hb content. In Tibetan antelope and Tibetan sheep, both Hb and Ang II were correlated positively with respective mPAP. In Tibetan antelope, FT 3 level was correlated positively with GH and negatively with ACTH. These results suggest that the endocrine system of Tibetan antelope is characterized by low energy expenditure and high stress, which may be one of the mechanisms underlying the Tibetan antelope adaptation to chronic hypoxia.