calling functions through a "pointer"

Hallo,

I wonder if there is a way to call functions in plpgsql having their oid.
As an example: suppose i have a table that contains oids to functions
and i have some statements that select some rows and must call the
corresponding functions. Of course i can do it using dynamic sql
(building the statement string on the fly), but this is much less
performing than direct sql written in plpgsq...

Thanks,

Max.