一个有逗号，一个没有，你看下

endogenous(varlist [, lagstruct(endlags, endmaxlags)]) specifies that a set of endogenous variables be included in the model.  Optionally, one may specify
        that endlags lags of the specified variables also be included.  The default for endlags is 0.  Specifying endmaxlags sets the maximum number of further
        lags of the endogenous variables that can be used as instruments.  The default is to include T_i-p-2 lagged levels as instruments for endogenous
        variables.  You may specify as many sets of endogenous variables as you need within the standard Stata limits on matrix size.  Each set of endogenous
        variables may have its own number of endlags and endmaxlags.

楼主解决了吗  我也想知道，能否请教下呢

如果用的是 xtabond 做的话，lag（m ，n）应该指的就是前定变量m阶滞后，至多以n个更高阶滞后项为工具变量。相当于lag（lags，maxldep）