where is NNTPSERVER variable set?

[the lone gunman <lgunman@crh3019.urh.uiuc.edu>]

I moved back to school, and now must use a different news server than
the one I used at home.  Where do I change where the NNTPSERVER
environment variable is originally initialized?  Changing
/etc/nntpserver doesn't seem to do it.

Thanks