Postnatal development of masticatory organs in rats II. Effects of hormones on the postnatal development of the M. masseter superficialis.
Postnatal development of masticatory organs in rats II. Effects of hormones on the postnatal development of the M. masseter superficialis.
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大鼠出生后咀嚼器官的发育II。
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
M. Kumegawa
中科院分区：
文献类型：
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作者：
N. Maeda;H. Hanai;M. Kumegawa
本文观察了L-甲状腺素(T4，0.2微克/克体重)和氢化可的松(HC，5微克/克体重)对发育期大鼠咬肌浅支的影响。T4和/或HC从出生后第5天起连续给药5d，可致大鼠肌纤维直径增加，SDH活性增加，不同肌纤维间活性差异，EDTA不敏感的ATPase活性早熟消失。这些激素对肌肉的作用在出生后第10天后逐渐减弱。在去甲状腺-去肾上腺的大鼠。T4增加了肌纤维的直径和SDH活性，并引起了纤维间SDH活性的差异，而HC则没有。因此，HC可能对SDH活性和肌纤维直径起到允许的作用。另一方面，仅用T4或HC处理时，EDTA不敏感的ATPase活性的肌肉纤维不会消失，但在T4和HC联合处理时会消失。这些结果提示，乳鼠T4和HC循环水平的升高与咬肌浅支的形成有关。
The effects of L-thyroxine (T4; 0.2 microgram/g body weight) an hydrocortisone (HC 5 microgram/g body weight) on the M. masseter superficialis in developing rats were investigated. Administration of T4 and/or HC to rats for 5 consecutive days from day 5 after birth induced precocious increase in diameter of the muscle fibers, increase of SDH activity and differences of the activity in various fibers and precocious disappearance of fibers with EDTA-insensitive ATPase activity. The effects of these hormones on the muscle gradually decreased after the 10th postnatal day. In thyroidectomized-adrenalectomized rats. T4 increased the diameter and SDH-activity of the muscle fibers and induced differences in SDH activity between fibers, but HC did not. Thus HC may act permissively on the SDH activity and the diameter of the muscle fibers. On the other hand, muscle fibers with EDTA-insensitive ATPase activity did not disappear on treatment with T4 or HC alone, but did disappear on treatment with T4 plus HC. These results suggest that increases in the circulating levels of T4 and HC in suckling rats are involved in development of the M. masseter superficialis.