This protein is called nerve growth factor (NGF).

这种蛋白质被称为神经生长因子（NGF.）

Human tumor cells expressed high levels of growth factor and its receptor.

人类肿瘤细胞表达高水平的生长因子及其受体。

For example, genes for insulin-like growth factor could enhance muscle mass.

例如，基因对于胰岛素增长因子能够导致肌肉量的增加。

Objective To explore the effects of insulin-like growth factor on the fetal growth.

目的探讨胰岛素样生长因子与胎儿生长发育的关系。

But there is a very real problem, and its name is Insulin-like Growth Factor-1 (IGF-1).

但这一个非常现实的问题，它的名字是胰岛素样生长因子- 1 (IGF - 1)。