Li J, Chow S Y
Department of Physiology, University of Utah School of Medicine, Salt Lake City 84108.
Neurochem Res. 1994 Jan;19(1):83-8. doi: 10.1007/BF00966733.
Activities of carbonic anhydrase and Na+,K(+)-ATPase in tissue homogenates and in subcellular fractions from different brain regions were studied in inherited primary hypothyroid (hyt/hyt) mice. The body weight, the weight of different brain regions, and the plasma thyroxine and triiodothyronine levels of hyt/hyt mice were significantly lower than those of the age-matched hyt/+ controls. In tissue homogenates of cerebral cortex, brain stem and cerebellum of hypothyroid mice, the activity of carbonic anhydrase (units/mg protein) was 59.2, 57.6, and 43.2%, and the activity of Na+,K(+)-ATPase (nmol Pi/mg protein/min) was 73.7, 74.4 and 68.7%, respectively, of that in corresponding regions of euthyroid littermates. The decrease in enzyme activity in tissue homogenates was also reflected in different subcellular fractions. In cerebral cortex and brain stem, carbonic anhydrase activity in cytosol, myelin and mitochondrial fractions of hypothyroid mice was about 45-50% of that in euthyroid mice, while in cerebellum the carbonic anhydrase activity in these subcellular fractions of hyt/hyt mice was only 33-38% of that in hyt/+ controls. Na+,K(+)-ATPase activity in myelin fraction of different brain regions of hyt/hyt mice was about 34-42% of that in hyt/+ mice, while in mitochondria, synaptosome and microsome fractions were about 44-52, 46-53, and 66-68%, respectively of controls. These data indicate that the activity of both carbonic anhydrase and Na+,K(+)-ATPase was affected more in the myelin than other subcellular fractions and more in the cerebellum than cerebral cortex and brain stem by deficiency of thyroid hormones.(ABSTRACT TRUNCATED AT 250 WORDS)
在遗传性原发性甲状腺功能减退（hyt/hyt）小鼠中，研究了不同脑区组织匀浆和亚细胞组分中碳酸酐酶及钠钾ATP酶的活性。hyt/hyt小鼠的体重、不同脑区重量以及血浆甲状腺素和三碘甲状腺原氨酸水平显著低于年龄匹配的hyt/+对照小鼠。在甲状腺功能减退小鼠的大脑皮层、脑干和小脑组织匀浆中，碳酸酐酶活性（单位/毫克蛋白）分别为甲状腺功能正常同窝小鼠相应脑区的59.2%、57.6%和43.2%，钠钾ATP酶活性（纳摩尔无机磷/毫克蛋白/分钟）分别为73.7%、74.4%和68.7%。组织匀浆中酶活性的降低也反映在不同亚细胞组分中。在大脑皮层和脑干中，甲状腺功能减退小鼠胞质溶胶、髓磷脂和线粒体组分中的碳酸酐酶活性约为甲状腺功能正常小鼠的45 - 50%，而在小脑中，hyt/hyt小鼠这些亚细胞组分中的碳酸酐酶活性仅为hyt/+对照小鼠的33 - 38%。hyt/hyt小鼠不同脑区髓磷脂组分中的钠钾ATP酶活性约为hyt/+小鼠的34 - 42%，而在线粒体、突触体和微粒体组分中分别约为对照的44 - 52%、46 - 53%和66 - 68%。这些数据表明，甲状腺激素缺乏对碳酸酐酶和钠钾ATP酶活性的影响在髓磷脂中比在其他亚细胞组分中更大，在小脑中比在大脑皮层和脑干中更大。（摘要截选至250字）
