Hodin R A, Chamberlain S M, Upton M P
Department of Surgery, Beth Israel Hospital, Boston, Massachusetts.
Gastroenterology. 1992 Nov;103(5):1529-36. doi: 10.1016/0016-5085(92)91174-3.
Thyroid hormone [triiodothyronine (T3)] has been shown to play a critical role in the growth and maturation of the mammalian small intestine, but its mechanism of action has not been well studied. In the current study, an animal model of hypothyroidism and hyperthyroidism was used to study the effects of T3 on the small intestine. Adult rats were treated with propylthiouracil for a 6-week period and then given injections of either saline (hypothyroid) or 30 micrograms/100 g body wt of T3 (hyperthyroid). Northern blot analyses showed marked differential regulation of brush border enzyme gene expression. Lactase messenger RNA (mRNA) levels decreased approximately 75% along the length of the small intestine, whereas sucrase levels were unchanged. The intestinal alkaline phosphatase mRNA species were upregulated by T3, especially the 3-kilobase band, which increased most dramatically in jejunum. Further experiments showed significant levels of both the alpha-1 and beta-1 T3 receptor mRNAs within the small intestinal mucosa. Histological examination showed that T3 treatment causes marked villus hyperplasia throughout the length of the small intestine. These results provide insight into the mechanism by which T3 exerts its influence on the growth and differentiation of the intestinal epithelium.
甲状腺激素[三碘甲状腺原氨酸（T3）]已被证明在哺乳动物小肠的生长和成熟过程中起关键作用，但其作用机制尚未得到充分研究。在本研究中，使用甲状腺功能减退和甲状腺功能亢进的动物模型来研究T3对小肠的影响。成年大鼠用丙硫氧嘧啶治疗6周，然后注射生理盐水（甲状腺功能减退）或30微克/100克体重的T3（甲状腺功能亢进）。Northern印迹分析显示刷状缘酶基因表达存在明显的差异调节。乳糖酶信使核糖核酸（mRNA）水平沿小肠长度下降约75%，而蔗糖酶水平未改变。肠碱性磷酸酶mRNA种类被T3上调，尤其是3千碱基条带，在空肠中增加最为显著。进一步的实验表明，小肠黏膜内α-1和β-1 T3受体mRNA水平均显著。组织学检查显示，T3治疗导致小肠全长明显的绒毛增生。这些结果为T3对肠上皮生长和分化产生影响的机制提供了见解。
