Verhaegen M, Correze C, Krug E, Nunez J
Mol Cell Endocrinol. 1979 Jun;14(3):167-80. doi: 10.1016/0303-7207(79)90042-x.
Thyroid hormones regulate lipid metabolism by affecting lipogenesis as well as lipolysis. The present paper discusses the way thyroidectomy induced an enhancement in lipogenesis in rat fat cells. The doubling in the conversion of glucose to CO2 and fatty acids seen after thyroidectomy was found to be due to a modification in the actual pathway of glucose metabolism: there was a preferential stimulation of the conversion of glucose to CO2 by the pentose cycle (utilisation of [1-14C]glucose) while the production of fatty acids and glyceride-glycerol proceeded, respectively, much more, or only slightly more, via the pathway of [6-14C]glucose metabolism. Studies employing the phosphodiesterase inhibitor MIX, or the cyclic AMP analogue, DBcAMP showed that the lipogenic process depends on cyclic AMP. As the stimulatory effect of thyroidectomy was not abolished, however, lipogenesis must be under the independent control of both cyclic AMP and absence of thyroid hormones. Insulin, a further mediator of lipogenesis was found to further enhance the already preexisting high conversion of glucose to CO2 in fat cells from thyroidectomized rats. It is concluded that at least three factors modify lipogenesis: thyroidectomy, cyclic AMP and insulin; each achieving its effect in an independent manner.
甲状腺激素通过影响脂肪生成和脂肪分解来调节脂质代谢。本文讨论了甲状腺切除术诱导大鼠脂肪细胞脂肪生成增强的方式。甲状腺切除术后葡萄糖向二氧化碳和脂肪酸转化的加倍被发现是由于葡萄糖代谢实际途径的改变：戊糖循环对葡萄糖向二氧化碳的转化有优先刺激作用（利用[1-14C]葡萄糖），而脂肪酸和甘油酯-甘油的产生分别通过[6-14C]葡萄糖代谢途径进行得更多或仅略多。使用磷酸二酯酶抑制剂MIX或环磷酸腺苷类似物DBcAMP的研究表明，脂肪生成过程依赖于环磷酸腺苷。然而，由于甲状腺切除术的刺激作用并未消除，脂肪生成必定受环磷酸腺苷和甲状腺激素缺乏的独立控制。胰岛素是脂肪生成的另一种介质，它被发现能进一步增强甲状腺切除大鼠脂肪细胞中已有的高葡萄糖向二氧化碳的转化率。得出的结论是，至少有三个因素会改变脂肪生成：甲状腺切除术、环磷酸腺苷和胰岛素；它们各自以独立的方式发挥作用。
