<PAGE>   1
                                                                     EXHIBIT 4.5



                          SECURITY AGREEMENT SUPPLEMENT

                  SECURITY AGREEMENT SUPPLEMENT, dated June 5, 1998, to the
Security Agreement, dated as of June 7, 1989 (the "SECURITY AGREEMENT"), made by
the Company and the corporations that are signatories thereto in favor of THE
CHASE MANHATTAN BANK (as successor to Chemical Bank (as successor to
Manufacturers Hanover Bank)), as agent (in such capacity, the "AGENT") for the
banks (the "BANKS") that are parties to the Credit Agreement referred to below.

                              W I T N E S S E T H :

                  WHEREAS, American Media Operations, Inc., a Delaware
corporation (the "COMPANY"), the Banks and the Agent are parties to a Credit
Agreement dated as of June 7, 1989 (the "ORIGINAL CREDIT AGREEMENT"), as amended
by the Amended and Restated Credit Agreement, dated as of June 28, 1990, the
Second Amended and Restated Credit Agreement, dated as of May 12, 1992, the
Third Amended and Restated Credit Agreement, dated as of November 10, 1994, and
the Fourth Amended and Restated Credit Agreement, dated as of June 5, 1998 (as
amended, supplemented or otherwise modified from time to time, the "CREDIT
AGREEMENT"), and, in connection therewith, the Company and certain of its
subsidiaries have executed and delivered the Security Agreement in favor of the
Agent; and

                  WHEREAS, pursuant to the provisions of subsection 7.3 of the
Original Credit Agreement the Company has agreed that, in the circumstances
described therein, it would cause certain persons which, after the date of the
Original Credit Agreement, became subsidiaries of the Company to become parties
to the Security Agreement by executing and delivering supplements thereto in the
form of this Security Agreement Supplement; and

                  WHEREAS, the undersigned (the "NEW PARTY"), which was not
originally a party to the Security Agreement, has become a Subsidiary of the
Company and wishes to become a party to the Security Agreement;

                  NOW, THEREFORE, the New Party and the Company hereby agree as
follows:

                  1. The New Party agrees to be bound by the provisions of the
         Security Agreement, and agrees that it shall on the date of this
         Supplement become a Party for all purposes of the Security Agreement to
         the same extent as if originally a Party thereto.

                  2. Schedules V, VI and VII of the Security Agreement are
         hereby supplemented by adding thereto the information set forth on
         Schedules I, II and III hereto, respectively.

                  3. The Company confirms and reaffirms the security interest in
         the Collateral (as defined in the Security Agreement) granted to the
         Agent, for the ratable benefit of the Banks under the Security
         Agreement, and as additional collateral


<PAGE>   2

                                                                               2








security for the prompt and complete payment and performance when due of all of
the Guarantee Obligations (as defined in the Security Agreement) and in order to
induce the Banks to make additional extensions of credit to the Company in
accordance with the terms of the Credit Agreement, the New Party hereby grants
to the Agent for the ratable benefit of the Banks a security interest in all of
the Collateral of such New Party.

                  4. To induce the Agent to accept this Security Agreement
         Supplement and to continue to extend credit to the Company pursuant to
         the Credit Agreement, (a) the Company hereby confirms that all the
         representations and warranties set forth in Section 3 of the Credit
         Agreement, insofar as they relate to "Credit Parties" and "Credit
         Documents", shall include the New Party and the Security Agreement, as
         supplemented by this Security Agreement Supplement, respectively, and
         hereby represents and warrants that such representations and warranties
         are correct in all material respects on the date hereof and (b) the
         Company and the New Party hereby confirm that all of the
         representations and warranties set forth in Section 4 of the Security
         Agreement, insofar as they relate to "Party", "Security Agreement" and
         "Collateral", shall include the New Party, the Security Agreement as
         supplemented by this Security Agreement Supplement and the Collateral
         of the New Party, respectively, and hereby represents and warrants that
         such representations and warranties are correct in all material
         respects on the date hereof.

                  5. Terms defined in the Credit Agreement shall have their
         defined meanings when used herein.

                  IN WITNESS WHEREOF, each of the undersigned has caused this
Security Agreement Supplement to be executed and delivered by a duly authorized
officer on the date first above written.

                                          AMERICAN MEDIA OPERATIONS, INC.


                                          By:
                                              ---------------------
                                              Title:


                                          FRONTLINE MARKETING, INC.

                                           By:
                                              ---------------------
                                              Title:


<PAGE>   3

                                                                               3

Accepted this 5th day of 
June, 1998.

THE CHASE MANHATTAN BANK,
as Agent

By:
   ------------------
   Title:


<PAGE>   4
                                                                               4






                                                            Schedule I
                                                            to Security
                                                            Agreement Supplement
                                                            --------------------



                     Location of Records Concerning Accounts
                     ---------------------------------------



                           10 Corbin Drive, 3rd Floor

                               Darien, CT  06820


<PAGE>   5


                                                                Schedule II
                                                                to Security
                                                            Agreement Supplement
                                                            --------------------



                      Locations of Inventory And Equipment
                      ------------------------------------

                           10 Corbin Drive, 3rd Floor
                                Darien, CT 06820

                          280 Madison Avenue, 6th Floor
                               New York, NY 10016

                             2201 East Willow Street
                                   Suite D-251

                             Signal Hill, CA  90806


<PAGE>   6
                                                                               6

                                                                Schedule III
                                                                to Security
                                                            Agreement Supplement

                  Chief Executive Offices, Principal Places of
              Business, Locations of Records Concerning Collateral
              ----------------------------------------------------

                           10 Corbin Drive, 3rd Floor
                                Darien, CT 06820


<PAGE>   7


                                                                               7



                          SECURITY AGREEMENT SUPPLEMENT

                  SECURITY AGREEMENT SUPPLEMENT, dated June 5, 1998, to the
Security Agreement, dated as of June 7, 1989 (the "SECURITY AGREEMENT"), made by
the Company and the corporations that are signatories thereto in favor of THE
CHASE MANHATTAN BANK (as successor to Chemical Bank (as successor to
Manufacturers Hanover Bank)), as agent (in such capacity, the "AGENT") for the
banks (the "BANKS") that are parties to the Credit Agreement referred to below.

                              W I T N E S S E T H :

                  WHEREAS, American Media Operations, Inc., a Delaware
corporation (the "COMPANY"), the Banks and the Agent are parties to a Credit
Agreement dated as of June 7, 1989 (the "ORIGINAL CREDIT AGREEMENT"), as amended
by the Amended and Restated Credit Agreement, dated as of June 28, 1990, the
Second Amended and Restated Credit Agreement, dated as of May 12, 1992, and the
Third Amended and Restated Credit Agreement, dated as of November 10, 1994, and
the Fourth Amended and Restated Credit Agreement, dated as of June 5, 1998 (as
amended, supplemented or otherwise modified from time to time, the "CREDIT
AGREEMENT"), and, in connection therewith, the Company and certain of its
subsidiaries have executed and delivered the Security Agreement in favor of the
Agent; and

                  WHEREAS, pursuant to the provisions of subsection 7.3 of the
Original Credit Agreement the Company has agreed that, in the circumstances
described therein, it would cause certain persons which, after the date of the
Original Credit Agreement, became subsidiaries of the Company to become parties
to the Security Agreement by executing and delivering supplements thereto in the
form of this Security Agreement Supplement; and

                  WHEREAS, the undersigned (the "NEW PARTY"), which was not
originally a party to the Security Agreement, has become a Subsidiary of the
Company and wishes to become a party to the Security Agreement;

                  NOW, THEREFORE, the New Party and the Company hereby agree as
follows:

                  1. The New Party agrees to be bound by the provisions of the
         Security Agreement, and agrees that it shall on the date of this
         Supplement become a Party for all purposes of the Security Agreement to
         the same extent as if originally a Party thereto.

                  2. Schedules V, VI and VII of the Security Agreement are
         hereby supplemented by adding thereto the information set forth on
         Schedules I, II and III hereto, respectively.

                  3. The Company confirms and reaffirms the security interest in
         the Collateral (as defined in the Security Agreement) granted to the
         Agent, for the ratable benefit of the Banks under the Security
         Agreement, and as additional collateral


<PAGE>   8
                                                                               8




security for the prompt and complete payment and performance when due of all of
the Guarantee Obligations (as defined in the Security Agreement) and in order to
induce the Banks to make additional extensions of credit to the Company in
accordance with the terms of the Credit Agreement, the New Party hereby grants
to the Agent for the ratable benefit of the Banks a security interest in all of
the Collateral of such New Party.

                  4. To induce the Agent to accept this Security Agreement
         Supplement and to continue to extend credit to the Company pursuant to
         the Credit Agreement, (a) the Company hereby confirms that all the
         representations and warranties set forth in Section 3 of the Credit
         Agreement, insofar as they relate to "Credit Parties" and "Credit
         Documents", shall include the New Party and the Security Agreement, as
         supplemented by this Security Agreement Supplement, respectively, and
         hereby represents and warrants that such representations and warranties
         are correct in all material respects on the date hereof and (b) the
         Company and the New Party hereby confirm that all of the
         representations and warranties set forth in Section 4 of the Security
         Agreement, insofar as they relate to "Party", "Security Agreement" and
         "Collateral", shall include the New Party, the Security Agreement as
         supplemented by this Security Agreement Supplement and the Collateral
         of the New Party, respectively, and hereby represents and warrants that
         such representations and warranties are correct in all material
         respects on the date hereof.

                  5. Terms defined in the Credit Agreement shall have their
         defined meanings when used herein.

                  IN WITNESS WHEREOF, each of the undersigned has caused this
Security Agreement Supplement to be executed and delivered by a duly authorized
officer on the date first above written.

                                           AMERICAN MEDIA OPERATIONS, INC.


                                           By:
                                              ---------------------
                                              Title:


                                           AMERICAN MEDIA MARKETING, INC.


                                           By:
                                              ---------------------
                                              Title:


<PAGE>   9

                                                                               9




Accepted this 5th day of 
June, 1998.

THE CHASE MANHATTAN BANK,
as Agent

By:
   --------------------
   Title:


<PAGE>   10


                                                                              10


                                                                  Schedule I
                                                                 to Security
                                                            Agreement Supplement
                                                            --------------------

                     Location of Records Concerning Accounts
                     ---------------------------------------

600 East Coast Avenue
Lantana, FL  33464


<PAGE>   11



                                                                 Schedule II
                                                                 to Security
                                                            Agreement Supplement
                                                            --------------------

                      Locations of Inventory and Equipment
                      ------------------------------------

None.


<PAGE>   12
                                                                              12

                                                                Schedule III
                                                                 to Security
                                                            Agreement Supplement
                                                            --------------------


                  Chief Executive Offices, Principal Places of
              Business, Locations of Records Concerning Collateral
              ----------------------------------------------------

                              600 East Coast Avenue
                                Lantana, FL 33464


<PAGE>   13

                                                                              13


                          SECURITY AGREEMENT SUPPLEMENT



                  SECURITY AGREEMENT SUPPLEMENT, dated June 5, 1998, to the
Security Agreement, dated as of June 7, 1989 (the "SECURITY AGREEMENT"), made by
the Company and the corporations that are signatories thereto in favor of THE
CHASE MANHATTAN BANK (as successor to Chemical Bank (as successor to
Manufacturers Hanover Bank)), as agent (in such capacity, the "AGENT") for the
banks (the "BANKS") that are parties to the Credit Agreement referred to below.

                              W I T N E S S E T H :

                  WHEREAS, American Media Operations, Inc., a Delaware
corporation (the "COMPANY"), the Banks and the Agent are parties to a Credit
Agreement dated as of June 7, 1989 (the "ORIGINAL CREDIT AGREEMENT"), as amended
by the Amended and Restated Credit Agreement, dated as of June 28, 1990, the
Second Amended and Restated Credit Agreement, dated as of May 12, 1992, and the
Third Amended and Restated Credit Agreement, dated as of November 10, 1994, and
the Fourth Amended and Restated Credit Agreement, dated as of June 5, 1998 (as
amended, supplemented or otherwise modified from time to time, the "CREDIT
AGREEMENT"), and, in connection therewith, the Company and certain of its
subsidiaries of the Company have executed and delivered the Security Agreement
in favor of the Agent; and

                  WHEREAS, pursuant to the provisions of subsection 7.3 of the
Original Credit Agreement the Company has agreed that, in the circumstances
described therein, it would cause certain persons which, after the date of the
Original Credit Agreement, became subsidiaries of the Company to become parties
to the Security Agreement by executing and delivering supplements thereto in the
form of this Security Agreement Supplement; and

                  WHEREAS, the undersigned (the "NEW PARTY"), which was not
originally a party to the Security Agreement, has become a Subsidiary of the
Company and wishes to become a party to the Security Agreement;

                  NOW, THEREFORE, the New Party and the Company hereby agree as
follows:

                  1. The New Party agrees to be bound by the provisions of the
         Security Agreement, and agrees that it shall on the date of this
         Supplement become a Party for all purposes of the Security Agreement to
         the same extent as if originally a Party thereto.

                  2. Schedules V, VI and VII of the Security Agreement are
         hereby supplemented by adding thereto the information set forth on
         Schedules I, II and III hereto, respectively.

                  3. The Company confirms and reaffirms the security interest in
         the Collateral (as defined in the Security Agreement) granted to the
         Agent, for the ratable benefit of the Banks under the Security
         Agreement, and as additional collateral


<PAGE>   14
                                                                              14




security for the prompt and complete payment and performance when due of all of
the Guarantee Obligations (as defined in the Security Agreement) and in order to
induce the Banks to make additional extensions of credit to the Company in
accordance with the terms of the Credit Agreement, the New Party hereby grants
to the Agent for the ratable benefit of the Banks a security interest in all of
the Collateral of such New Party.

                  4. To induce the Agent to accept this Security Agreement
         Supplement and to continue to extend credit to the Company pursuant to
         the Credit Agreement, (a) the Company hereby confirms that all the
         representations and warranties set forth in Section 3 of the Credit
         Agreement, insofar as they relate to "Credit Parties" and "Credit
         Documents", shall include the New Party and the Security Agreement, as
         supplemented by this Security Agreement Supplement, respectively, and
         hereby represents and warrants that such representations and warranties
         are correct in all material respects on the date hereof and (b) the
         Company and the New Party hereby confirm that all of the
         representations and warranties set forth in Section 4 of the Security
         Agreement, insofar as they relate to "Party", "Security Agreement" and
         "Collateral", shall include the New Party, the Security Agreement as
         supplemented by this Security Agreement Supplement and the Collateral
         of the New Party, respectively, and hereby represents and warrants that
         such representations and warranties are correct in all material
         respects on the date hereof.

                  5. Terms defined in the Credit Agreement shall have their
         defined meanings when used herein.

                  IN WITNESS WHEREOF, each of the undersigned has caused this
Security Agreement Supplement to be executed and delivered by a duly authorized
officer on the date first above written.

                                           AMERICAN MEDIA OPERATIONS, INC.

                                           By:
                                              ------------------------
                                              Title:

                                           RETAIL MARKETING NETWORK, INC.


                                           By:
                                              ------------------------
                                              Title:


<PAGE>   15
                                                                              15


Accepted this 5th day of 
June, 1998.

THE CHASE MANHATTAN BANK,
as Agent

By:
   ------------------
   Title:


<PAGE>   16
                                                                              16


  

                                                                 Schedule I
                                                                 to Security
                                                            Agreement Supplement




                     Location of Records Concerning Accounts
                     ---------------------------------------

                              600 East Coast Avenue

                               Lantana, FL  33464


<PAGE>   17


                                                                Schedule II
                                                                to Security
                                                            Agreement Supplement
                                                            --------------------

                      Locations of Inventory And Equipment
                      ------------------------------------

None.


<PAGE>   18
                                                                              18

                                                                Schedule III
                                                                 to Security
                                                            Agreement Supplement
                                                            --------------------



                  Chief Executive Offices, Principal Places of
              Business, Locations of Records Concerning Collateral
              ----------------------------------------------------

                              600 East Coast Avenue
                                Lantana, FL 33464