低氧暴露对大鼠下丘脑CRF分泌的影响

目的和方法：利用人工模拟低氧及放射免疫测定（RIA）法,观察不同低氧（5km,7km）暴露对大鼠下丘脑分泌促肾上腺皮质激素释放激素（C orticotropin-releasing factor,CRF）的作用和血浆皮质酮水平的变化。比较低氧暴露不同时间（2h,24h,5d,15d）后,大鼠下丘脑CRF分泌和血浆皮质酮的变化。结果：低氧暴露2h,24h后下丘脑的CRF分泌明显增加,血浆皮质酮水平显著升高,这种变化随着低氧程度的加深而增强,随着低氧暴露时间的延长（5d）上述变化减弱。至慢性低氧暴露15d后,下丘脑CRF分泌及血浆皮质酮水平与对照组相比已无显著差异,基本恢复到对照水平。结论：动物暴露于低氧环境后,下丘脑CRF分泌及血浆皮质酮水平变化为：低氧暴露2h,24h后CRF分泌和皮质酮分泌被激活;低氧暴露5d后CRF分泌和皮质酮分泌活动减弱,并开始恢复;至低氧暴露15d后,这种分泌活动基本恢复,进入恢复期。

Effect of hypoxia on activity of hypothalamo-pituitary- adrenal-cortex axis in rat

Aim and Methods: In this experiment we used the methods of simulated hypoxia in a low pressure cabin and RIA to investigate the effect of hypoxia on secretion of corticotropin releasing factor (CRF) from hypotholamus and corticosterone from adrenal cortex. And compare the effects of hypoxia on secretion of CRF and corticosterone in rat exposed to hypoxia for different time. Results: During acute hypoxia the secretion of CRF and level of plasma corticosterone rose significantly comparing with control. After 5 days of exposed to hypoxia the augment of secretion of CRF and level of plasma corticosterone decresed and to 15 days exposed to hypoxia the secretion of CRF and level of plasma corticosterone approached to control. Conclusion: Hypoxia(2 h, 24 h)significantly activated HPA axis. After 5 days exposed to hypoxia the activity of HPA axis attenuated and began to recovery. After 15 days exposed to chronic hypoxia the activity of HPA axis has recovered to control level.