过量蛋氨酸对大鼠不同脑区L－〔^（35）S〕蛋氨酸掺入量的影响

INFLUENCE OF EXCESS DIETARY METHIONINE ON L一[35S]METHIONINE INCORPORATION INTO DIFFERENT BRAIN AREASIN RATS

本文观察了过量蛋氨酸对大鼠大脑额叶、颞叶和下丘脑等脑区以及大鼠肝组织Ｌ－［３５Ｓ］Ｍｅｔ掺入的变化。实验分三组，以基础饲料为对照组，基础饲料添加０．２％ＤＬ一蛋氨酸为适量蛋氨酸组，基础饲料添加２．０％ＤＬ一蛋氨酸为过量蛋氨酸组，饲养２１天，断头杀鼠取上述组织作离体Ｌ－［３５Ｓ］Ｍｅｔ核素标记。结果表明大鼠进食添加２．０ＤＬ一蛋氨酸饲料，鼠脑额叶及颞叶脑区［３５Ｓ］Ｍｅｔ掺入量与对照及适量蛋氨酸组基本一致。在下丘脑区，饲料蛋氨酸水平低，标记的Ｍｅｔ掺入量也低；添加２．０％蛋氨酸组，Ｌ－［３５Ｓ］Ｍｅｔ掺入量明显增加。表明过量蛋氨酸对上述各区脑组织无不良影响。相反，进食过量蛋氨酸，鼠肝Ｌ－［３５Ｓ］Ｍｅｔ掺入量比其他两组明显降低，蛋白质代谢障碍。

ccording to the levcl of methionine(Met)in diets,rats were rando一 mly divided into 3 groups:group A(basic diet);group B(basic diet+ 0.2% DL一Met)and group C(basic diet + 2.0%DL-Met).The animals were killed after feeding for 21 days.Cerebral lobus frontalis,lobus temporalis andhypothalamus were removed and determined after incubating in vitro withL-[35S] methionine(L-[35S]Met).At the samc time, hepatic tissue wastreated in the same manner as brain,The results showed that no significantdifference of L-[35S] Met incorporated into lobus frontalis and lobus tempo-ralis was found among 3 groups,whereas incorporated content of L-[35S]MetWas increased markedly in rat hypothalamus by 2.0% DL-Met supplemen-tation,In contrast,incorporation of labeled Met into hepatic tissue wasdecreased significantly with 2.0% DL-Met fed.The data supported previous observations that there was harmful influence upon liver,but not on brain when excess Met was given。