Faas F H, Carter W J
Biochem J. 1982 Oct 1;207(1):29-35. doi: 10.1042/bj2070029.
We have studied the influence of experimental hypothyroidism in the rat on the synthesis of unsaturated fatty acids and on liver microsomal lipid fatty acid composition. Hypothyroid rats demonstrated an 80% decrease in delta 9 (stearate) desaturation and a 43% decrease in delta 6 (linoleate) desaturation. Liver microsomal fatty acid composition was altered in the hypothyroid animals with a significantly decreased proportion of arachidonate and increased proportions of linoleate, eicosa-8,11,14-trienoate, eicosapentaenoate and docosahexaenoate. The bulk of these changes occurred in both of the two major phospholipid components, phosphatidylcholine and phosphatidylethanolamine. All of the changes were corrected by treatment of the hypothyroid rat with 25 micrograms of tri-iodothyronine/100 g body wt. twice daily. The diminished delta 9 desaturation did not lead to any changes in fatty acid composition. The increased linoleate and decreased arachidonate levels may be due to the diminished delta 6 desaturase activity, the rate-controlling step in the conversion of linoleate into arachidonate. The increases in the proportions of the other polyunsaturated fatty acid components cannot be explained by changes in the synthesis of unsaturated fatty acids, but are probably due to diminished utilization of these fatty acids.
我们研究了大鼠实验性甲状腺功能减退对不饱和脂肪酸合成及肝脏微粒体脂质脂肪酸组成的影响。甲状腺功能减退的大鼠9位（硬脂酸）去饱和作用降低了80%，6位（亚油酸）去饱和作用降低了43%。甲状腺功能减退的动物肝脏微粒体脂肪酸组成发生改变，花生四烯酸比例显著降低，亚油酸、8,11,14-二十碳三烯酸、二十碳五烯酸和二十二碳六烯酸比例增加。这些变化大部分发生在两种主要磷脂成分，即磷脂酰胆碱和磷脂酰乙醇胺中。用25微克三碘甲状腺原氨酸/100克体重每日两次治疗甲状腺功能减退的大鼠可纠正所有这些变化。9位去饱和作用减弱并未导致脂肪酸组成发生任何变化。亚油酸水平升高和花生四烯酸水平降低可能是由于6位去饱和酶活性降低，这是亚油酸转化为花生四烯酸过程中的限速步骤。其他多不饱和脂肪酸成分比例的增加不能用不饱和脂肪酸合成的变化来解释，可能是由于这些脂肪酸的利用减少。
