Sood A, Schwartz H L, Oppenheimer J H
Department of Medicine, University of Minnesota, Minneapolis 55455, USA.
Biochem Biophys Res Commun. 1996 May 15;222(2):287-91. doi: 10.1006/bbrc.1996.0736.
Two recent studies have claimed that thyroid hormone administration accelerates malic enzyme gene expression in the neonatal brain in contrast to the well-documented lack of effect of triiodothyronine on malic enzyme gene expression in the adult brain. Since these observations conflict with earlier observations in our laboratory, we reinvestigated the effect of thyroid hormone status on the ontogeny of malic enzyme gene expression in the neonatal rat. Neither hypothyroidism nor hyperthyroidism influenced the ontogenesis of malic enzyme activity in neonatal brain whereas the patterns of gene expression and enzyme activity in liver were markedly affected. Our results suggest that tissue-specific factors in brain block thyroid hormone-induced gene expression by thyroid hormone.
最近的两项研究表明，与三碘甲状腺原氨酸对成年大脑苹果酸酶基因表达缺乏影响这一已有充分记录的情况相反，给予甲状腺激素会加速新生大脑中苹果酸酶基因的表达。由于这些观察结果与我们实验室早期的观察结果相矛盾，我们重新研究了甲状腺激素状态对新生大鼠苹果酸酶基因表达个体发育的影响。甲状腺功能减退和甲状腺功能亢进均未影响新生大脑中苹果酸酶活性的个体发育，而肝脏中的基因表达模式和酶活性则受到显著影响。我们的结果表明，大脑中的组织特异性因子会阻止甲状腺激素诱导的甲状腺激素基因表达。
