Sidransky H, Verney E
Lab Invest. 1975 Jan;32(1):65-70.
The influence of the quantity of diet on protein synthesis of rats force-fed a complete diet or one free of threonine for 3 days. Protein synthesis was studied. The results revealed that rats force-fed an adequate amount (6.5 gm. per day) of threonine-devoid diet demonstrated increased hepatic and cardiac protein synthesis and decreased skeletal muscle and splenic protein synthesis in comparison to the results with rats force-fed the complete diet. In contrast, rats force-fed one-half the quantity (3.25 gm. per day) of the diets revealed no or small differences in protein synthesis of the liver, heart, gastrocnemius muscle, and spleen between the rats force-fed the complete and the threonine-devoid diets, although both of the one-half quantity groups had values which were decreased in comparison to those of rats force-fed the adequate quantity of complete diet. The tube feeding of L-threonine (60 mg.) to rats force-fed one-half the quantity of the complete or threonine-devoid diet on the 4th morning 2 hours before killing did not influence the results of organ protein synthesis. Protein synthesis was studied in vivo by measuring 14C-leucine incorporation into organ proteins and in vitro by measuring 14C-leucine incorporation into proteins by using postmitochondrial supernatants or microsomes of livers. Sucrose density gradients of hepatic polyribosomes were studied and revealed that there were more aggregated polyribosomes in rats force-fed adequate quantities of the experimental diets than in those force-fed the control diets. Rats force-fed one-half quantity of the complete and threonine-devoid diets revealed similar polyribosomal patterns which revealed more disaggregation than those in rats ofrce-fed the adequate quantity of complete diet.
日粮数量对强制喂食完全日粮或不含苏氨酸日粮3天的大鼠蛋白质合成的影响。对蛋白质合成进行了研究。结果显示，与强制喂食完全日粮的大鼠相比，强制喂食适量（每天6.5克）不含苏氨酸日粮的大鼠肝脏和心脏蛋白质合成增加，骨骼肌和脾脏蛋白质合成减少。相比之下，强制喂食日粮数量减半（每天3.25克）的大鼠，在强制喂食完全日粮和不含苏氨酸日粮的大鼠之间，肝脏、心脏、腓肠肌和脾脏的蛋白质合成没有差异或差异很小，尽管两个数量减半组的值与强制喂食适量完全日粮的大鼠相比都有所降低。在处死前4天上午2小时，对强制喂食完全日粮或不含苏氨酸日粮数量减半的大鼠经管饲L-苏氨酸（60毫克），并未影响器官蛋白质合成的结果。通过测量14C-亮氨酸掺入器官蛋白质来研究体内蛋白质合成，通过使用肝脏的线粒体后上清液或微粒体测量14C-亮氨酸掺入蛋白质来研究体外蛋白质合成。对肝脏多核糖体的蔗糖密度梯度进行了研究，结果显示，强制喂食适量实验日粮的大鼠比强制喂食对照日粮的大鼠有更多聚集的多核糖体。强制喂食完全日粮和不含苏氨酸日粮数量减半的大鼠显示出相似的多核糖体模式，与强制喂食适量完全日粮的大鼠相比显示出更多的解聚。
