Kawada J, Mino H, Nishida M, Yoshimura Y
Department of Biochemistry, Faculty of Pharmaceutical Sciences, University of Tokushima, Japan.
Neuroendocrinology. 1988 May;47(5):424-30. doi: 10.1159/000124945.
Hypothyroidism was induced in rats by treatment with propylthiouracil through the mother's milk throughout the suckling period followed by surgical thyroidectomy without use of radioiodine. The growth of these animals was considerably retarded and their light-dark discriminative operant learning ability was also significantly decreased. Replacement therapy with thyroxine to maintain its normal serum concentration was effective for continuing normal growth and development of learning ability. Therefore, these hypothyroid rats are a useful model of congenital hypothyroidism. Biochemical studies showed that the inhibition of cerebral Na,K-ATPase and succinic dehydrogenase activities detected in early postnatal life in these hypothyroid rats was transient and that normal activities of these enzymes were later regained in adult rats. However, the activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase and the brain myelin remained low throughout life unless thyroxine was administered. Though a critical correlation between biochemical parameters and learning ability is still uncertain, these results suggest that the formation of myelin in the neonatal period is at least dependent on thyroid hormone and would play an important role in mental development.
在哺乳期，通过丙硫氧嘧啶经母乳给药诱导大鼠发生甲状腺功能减退，随后进行甲状腺切除术，不使用放射性碘。这些动物的生长明显迟缓，它们的明暗辨别操作性学习能力也显著下降。用甲状腺素进行替代治疗以维持其正常血清浓度，对继续正常生长和学习能力发育有效。因此，这些甲状腺功能减退大鼠是先天性甲状腺功能减退的有用模型。生化研究表明，这些甲状腺功能减退大鼠在出生后早期检测到的脑钠钾ATP酶和琥珀酸脱氢酶活性抑制是短暂的，成年大鼠后期这些酶的活性恢复正常。然而，除非给予甲状腺素，2',3'-环核苷酸3'-磷酸水解酶的活性和脑髓磷脂在整个生命过程中都保持较低水平。尽管生化参数与学习能力之间的关键相关性仍不确定，但这些结果表明，新生儿期髓磷脂的形成至少依赖于甲状腺激素，并且在智力发育中起重要作用。
