You can run system procedures from any database. If a system procedure is executed from a database other than the sybsystemprocs database, any references to system tables are mapped to the database from which the procedure is executed.
For example, if the database owner of pubs2 runs sp_adduser from pubs2, the new user is added to pubs2..sysusers. To run a system procedure in a specific database, either open that database with the use command and execute the procedure, or qualify the procedure name with the database name.
When the parameter for a system procedure is an object name, and the object name is qualified by a database name or owner name, the entire name must be enclosed in single or double quotes.