When the researchers doubled the amount of tryptophan in the mice's feed, the number of such cells rose by about 50 percent but when tryptophan levels were halved, the number of cells dropped by half.
当研究人员将小白鼠饲料中的色氨酸数量翻倍后，这类细胞的数量增加了大约 50％，但当色氨酸水平减半时，细胞数量减少了一半。