冷刺激对鼠Ⅱ型5’脱碘酶活性的影响

CHANGES IN THYROXINE MONODEIODINATION DURING ACUTE COLD EXPOSURE IN MICE,RATS AND SYRIAN HAMSTERS

本研究观察了在冷环境4℃中的小白鼠、大白鼠和叙利亚仑鼠的棕色脂肪组织、垂体前叶、大脑皮质和副泪腺等组织中的Ⅱ型5′脱碘酶的活性。在三种动物中,冷刺激90、180和270分钟后引起棕色脂肪组织中Ⅱ型5′脱碘酶活性明显升高,而垂体前叶中该酶的活性降低。在大白鼠的大脑皮质中该酶活性升高,而在副泪腺中下降。叙利亚仑鼠副泪腺中该酶活性无改变。这些改变与动物适应冷环境的机制有关。

Thyroxine 5'deiodinase type Ⅱ(5'D—Ⅱ)activity in brown adipose tissue(BAT),anterior pituitary gland,cerebrocortex,and Harderian glands(HG)was investigated in mice,rats and syryan ham- sters acutely exposed to cold(4℃).In rats,mice and hamsters,cold exposure for either 90,180 or 270 min caused a highly significant rise in BAT 5'D—Ⅱ activity;these changes were apparent within 90 min after cold exposure and persisted to the conclusion of the study(270 min).Cold treatment led to significant reductions in 5'D—Ⅱ activity in the pituitary gland of all three species.In the rat,but not in the hamster,cerebrocortical 5'D—Ⅱ activity rose in response to cold exposure while in the HG,monodeiodination decreased in the rat during cold exposure and remained unchanged in the hamster.The changes likely relate to the mechanisms of cold adaptateon in these species.