How to insert into pg_largeobject?

Hi,

How can I insert data into pg_largeobject?

When I try:

INSERT INTO pg_catalog.pg_largeobject(loid, pageno, data) VALUES (4,
1, '\\001\\002\\003\\004');

as a non-superuser, I get:

ERROR: permission denied for relation pg_largeobject
SQL state: 42501

Even after I granted privileges like this:

magazine_test=# GRANT ALL ON pg_largeobject TO public;
GRANT
magazine_test=# \dp pg_catalog.pg_largeobject
Access privileges for database "magazine_test"
Schema | Name | Type | Access privileges
------------+----------------+-------+---------------------------------------------
pg_catalog | pg_largeobject | table |
{=arwdRxt/postgres,ognjen=arwdRxt/postgres}
(1 row)

Is the privileges problem here, or something else?

-Ognjen