EXHIBIT 10.13
                                       
                    FIRST AMENDMENT TO FIRST AMENDED AND RESTATED 
                              REVOLVING LOAN AGREEMENT

     THIS FIRST AMENDMENT TO FIRST AMENDED AND RESTATED REVOLVING LOAN 
AGREEMENT (this "Amendment") made this 21st day of October, 1998, by and 
among ALEXANDRIA REAL ESTATE EQUITIES, INC., a Maryland corporation 
("Parent"), ALEXANDRIA REAL ESTATE EQUITIES, L.P., a Delaware limited 
partnership ("Operating Partnership"), ARE-QRS CORP., a Maryland corporation 
("QRS"), ARE ACQUISITIONS, LLC, a Delaware limited liability company ("ARE"), 
the other Borrowers whose names are set forth on the signature pages of this 
Amendment (collectively, with Parent, Operating Partnership, QRS and ARE, the 
"Borrowers", all on a joint and several basis), each lender whose name is set 
forth on the signature pages of this Amendment as "Banks" (collectively, the 
"Banks" and individually, a "Bank") and BANKBOSTON, N.A., as Managing Agent 
(the "Managing Agent").
                                       
                                 W I T N E S S E T H:

     WHEREAS, Borrowers, Managing Agent and certain of the Banks entered into 
that certain First Amended and Restated Revolving Loan Agreement dated as of 
August 4, 1998 (the "Loan Agreement"); and

     WHEREAS, BankBoston has assigned a portion of its Commitment to certain 
of the other Banks; 

     WHEREAS, Borrowers have requested that Managing Agent and the Banks 
modify certain provisions of the Loan Agreement; and

     WHEREAS, as a condition to such modification, Managing Agent and the 
Banks have required that Borrowers execute this Amendment;

     NOW, THEREFORE, for and in consideration of the sum of TEN and NO/100 
DOLLARS ($10.00), and other good and valuable consideration, the receipt and 
sufficiency of which is hereby acknowledged, the parties hereto do hereby 
covenant and agree as follows:

     1.   DEFINITIONS.  All the terms used herein which are not otherwise 
defined herein shall have the meanings set forth in the Loan Agreement.

     2.   MODIFICATION OF THE LOAN AGREEMENT.  Borrowers, the Banks and 
Managing Agent do hereby modify and amend the Loan Agreement as follows: 

          (a)  By deleting in its entirety the definition of the term 
"Borrowing Base" appearing in Section 1.1 of the Loan Agreement, and 
inserting in lieu thereof the following:
                                       


          "'BORROWING BASE' means, as of any date of determination, the LESSER
          OF (a) the maximum amount which, when added to the total outstanding
          balance of all unsecured Indebtedness of Parent and its Subsidiaries
          (including the Loans), would not exceed fifty-seven and one-half
          percent (57.5%) of the aggregate Asset Value of the Unencumbered Asset
          Pool, and (b) the maximum amount which would not cause the Test Debt
          Service Coverage Amount for the Unencumbered Asset Pool to be less
          than two (2).  Notwithstanding the foregoing, commencing on the first
          to occur of (i) the occurrence of (A) any Equity Offering or (B) the
          encumbrance of any Real Estate which as of October 1, 1998 was  
          Unencumbered (excluding the Encumbrance of any such Real Estate for
          the purpose of obtaining a construction loan to finance the
          construction of improvements to such Real Estate) if such event (i.e.
          (A) or (B)) results in net proceeds greater than $20,000,000.00 and
          if, after giving effect to such occurrence the Borrowers would be in
          compliance with all of their obligations and covenants relating to the
          Borrowing Base if the figure 'fifty-seven and one-half percent
          (57.5%)' appearing in clause (a) of this definition were reduced to
          'fifty percent (50%)', and (ii) June 1, 1999, and continuing at all
          times thereafter, the figure 'fifty-seven and one-half percent
          (57.5%)' appearing in clause (a) of this definition shall be reduced
          to 'fifty percent (50%).'"; and 

          (b)  By deleting in its entirety Schedule 1 to EXHIBIT E, and
inserting in lieu thereof Schedule 1 attached hereto and made a part hereof.

     3.   MODIFICATION FEE.  Upon the execution hereof, Borrowers shall pay to
the Managing Agent for the account of the Banks in accordance with their
separate agreement a fee as set forth in a separate agreement between the
Borrowers and the Managing Agent.  Managing Agent shall pay to each of the Banks
a portion of such fee in accordance with their separate agreement.  Such fee
shall be fully earned when paid and non-refundable under any circumstances.  

     4.   REFERENCES TO LOAN AGREEMENT.  All references in the Loan Documents to
the Loan Agreement shall be deemed a reference to the Loan Agreement, as
modified and amended herein.

     5.   REPRESENTATIONS.  Borrowers represent and warrant to Managing Agent
and the Banks as follows:

          (a)  Each of the Borrowers has all requisite power and authority to
execute and deliver this Amendment and to perform its obligations hereunder.

          (b)  The execution, delivery and performance by each of Borrowers of
this Amendment have been duly authorized by all necessary corporate, partnership
or limited liability company action, as applicable, and do not and will not:

                                       -2-



               (i)    Require any consent or approval not heretofore obtained
                      of any partner, director, stockholder, security holder or
                      creditor of Borrowers;

               (ii)   Violate or conflict with any provision of Borrowers'
                      charter, articles of incorporation, bylaws or other
                      organizational agreements, as applicable;

               (iii)  Result in or require the creation or imposition of any
                      Lien or Right of Others upon or with respect to any
                      Property now owned or leased or hereafter acquired by
                      Borrowers;

               (iv)   Violate any Requirement of Law applicable to Borrowers;
                      or

               (v)    Result in a breach of or constitute a default under, or
                      cause or permit the acceleration of any obligation owed
                      under, any indenture or loan or credit agreement or any
                      other Contractual Obligation to which Borrowers are a
                      party or by which Borrowers or any of their Property is
                      bound or affected.

          (c)  Except as previously obtained or made, no authorization, consent,
approval, order, license or permit from, or filing, registration or
qualification with, any Governmental Agency is or will be required to authorize
or permit under applicable Laws the execution, delivery and performance by any
of Borrowers of this Amendment.

          (d)  This Amendment will, when executed and delivered by Borrowers,
constitute the legal, valid and binding obligation of Borrowers, enforceable
against Borrowers in accordance with its terms, EXCEPT as enforcement may be
limited by Debtor Relief Laws or equitable principles relating to the granting
of specific performance and other equitable remedies as a matter of judicial
discretion.

     6.   CONDITIONS TO EFFECTIVENESS.  The effectiveness of this Amendment is
subject to the satisfaction of each of the following conditions precedent:

          (a)  The Managing Agent shall have received all of the following, each
of which shall be originals unless otherwise specified, each properly executed
by a Responsible Official of each party thereto, and each in form and substance
satisfactory to the Managing Agent and its legal counsel (unless otherwise
specified or, in the case of the date of any of the following, unless the
Managing Agent otherwise agrees or directs):

               (i)    at least one (1) executed counterpart of this Amendment,
                      together with arrangements satisfactory to the Managing
                      Agent for 

                                       -3-



                      additional executed counterparts, sufficient in number 
                      for distribution to the Banks and Borrowers;

               (ii)   with respect to each of Borrowers, such documentation as
                      the Managing Agent may require to establish its authority
                      to execute, deliver and perform this Amendment, the
                      identity, authority and capacity of each Responsible
                      Official thereof authorized to act on its behalf,
                      INCLUDING certified copies of articles of incorporation
                      and amendments thereto, bylaws and amendments thereto (or
                      certifications acceptable to Managing Agent that there
                      have been no changes to any of such items from those
                      previously delivered to the Managing Agent pursuant to
                      the Loan Agreement), certificates of good standing and/or
                      qualification to engage in business, tax clearance
                      certificates, certificates of corporate resolutions,
                      incumbency certificates, Certificates of Responsible
                      Officials, and the like; and

               (iii)  opinions of counsel to the Borrowers in form and
                      substance satisfactory to the Managing Agent;

          (b)  The fee payable pursuant to Paragraph 3 shall have been paid.

          (c)  The Managing Agent shall have reviewed such other documents,
instruments, certificates, opinions, assurances, consents and approvals as the
Managing Agent or the Managing Agent's special counsel may reasonably have
requested.

     7.   NO DEFAULT.  By execution hereof, each of the Borrowers certifies that
such Persons are and will be in compliance with all covenants under the Loan
Documents after the execution and delivery of this Amendment, and that no
Default or Event of Default has occurred and is continuing.  

     8.   WAIVER OF CLAIMS. Each of the Borrowers acknowledges, represents and
agrees that none of such Persons has any defenses, setoffs, claims,
counterclaims or causes of action of any kind or nature whatsoever with respect
to the Loan Documents, the administration or funding of the Loan or with respect
to any acts or omissions of Managing Agent or any Bank, or any past or present
officers, Managing Agents or employees of Managing Agent or any Bank, and each
of such Persons does hereby expressly waive, release and relinquish any and all
such defenses, setoffs, claims, counterclaims and causes of action, if any.

     9.   RATIFICATION.  Except as hereinabove set forth, all terms, covenants
and provisions of the Loan Agreement remain unaltered and in full force and
effect, and the parties hereto do hereby expressly ratify and confirm the Loan
Documents and the Loan Agreement as modified and amended herein.  Nothing in
this Amendment shall be deemed or construed to constitute, and there has not
otherwise occurred, a novation, cancellation, satisfaction, release, waiver,
extinguishment or substitution of the indebtedness evidenced by the Notes or the
other obligations of Borrowers under the Loan Documents. 

                                       -4-



     10.  AMENDMENT AS LOAN DOCUMENT.  This Amendment shall constitute a Loan
Document.  

     11.  COUNTERPARTS.  This Amendment may be executed in any number of
counterparts which shall together constitute but one and the same agreement.

     12.  MISCELLANEOUS.  This Amendment shall be construed and enforced in
accordance with the laws of the State of California.  This Amendment shall be
binding upon and shall inure to the benefit of the parties hereto and their
respective permitted successors, successors-in-title and assigns as provided in
the Loan Agreement.





                           [Signatures on Following Pages.]

                                       -5-



     IN WITNESS WHEREOF, the parties hereto have hereto set their hands and
affixed their seals as of the day and year first above written.

                              BORROWERS:

                              ALEXANDRIA REAL ESTATE EQUITIES, INC.



                              By: /s/ PETER J. NELSON
                                  ---------------------------------
                                    Its: C.F.O.

                              ALEXANDRIA REAL ESTATE EQUITIES, L.P.

                              By:  ARE-QRS Corp., its general partner



                                   By: /s/ PETER J. NELSON
                                       -----------------------------
                                         Its: C.F.O.

                              ARE-QRS CORP.



                              By: /s/ PETER J. NELSON
                                  ---------------------------------
                                    Its: C.F.O.

                              ARE ACQUISITIONS, LLC
                              ARE-708 QUINCE ORCHARD, LLC
                              ARE-940 CLOPPER ROAD, LLC
                              ARE-1201 HARBOR BAY, LLC
                              ARE-1401 RESEARCH BOULEVARD, LLC
                              ARE-1500 EAST GUDE, LLC

                              By:  ARE-QRS Corp., their managing member

                                   By: /s/ PETER J. NELSON
                                       ----------------------------
                                         Its: C.F.O.

                                       -6-




                              ARE-4757 NEXUS CENTRE, LLC
                              ARE-215 COLLEGE ROAD, LLC
                              ARE-819/863 MITTEN ROAD, LLC
                              ARE-6166 NANCY RIDGE, LLC
                              ARE-150/154 TECHNOLOGY PARKWAY, LLC
                              ARE-8000/9000/10000 VIRGINIA MANOR, LLC
                              ARE-19 FIRSTFIELD ROAD, LLC
                              ARE-10150 OLD COLUMBIA, LLC
                              ARE-11025 ROSELLE STREET, LLC
                              ARE-100/800/801 CAPITOLA, LLC
                              ARE-170 WILLIAMS DRIVE, LLC
                              ARE-3005 FIRST AVENUE, LLC
                              ARE-15020 SHADY GROVE, LLC    

                              By:  Alexandria Real Estate Equities, L.P., their
                                   sole member

                                   By:  ARE-QRS Corp., its general partner


                                   By: /s/ PETER J. NELSON
                                       ----------------------------
                                         Its: C.F.O.

                              ARE-79/96 CHARLESTOWN NAVY YARD, LLC
                              ARE-280 POND STREET, LLC

                              By:  AREE-Holdings, L.P., their managing member

                                   By:  ARE-GP Holdings QRS Corp., its general
                                        partner


                                   By: /s/ PETER J. NELSON
                                       ----------------------------
                                         Its: C.F.O.

                                       -7-



                              ARE-5100/5110 CAMPUS DRIVE, L.P.
                              ARE-702 ELECTRONIC DRIVE

                              By:  AREE-Holdings, L.P., their general partner

                                   By:  ARE-GP Holdings QRS Corp., its general
                                        partner


                                        By: /s/ PETER J. NELSON
                                            ----------------------------
                                              Its: C.F.O.


                              ARE-10933 NORTH TORREY PINES, LLC
                              ARE-11099 NORTH TORREY PINES, LLC

                              By:  Alexandria Real Estate Equities, Inc., their
                                   sole member


                                   By: /s/ PETER J. NELSON
                                       ----------------------------
                                         Its: C.F.O.


                              BANKS AND MANAGING AGENT:

                              BANKBOSTON, N.A., individually and as Managing
                              Agent


                              By: /s/ DANIEL P. STEGEMOELLER
                                  ---------------------------------
                                    Its: Vice President


                              SOCIETE GENERALE SOUTHWEST AGENCY, individually
                              and as Syndication Agent


                              By: /s/ SCOTT GOSSLEE
                                  ---------------------------------
                                    Its: Vice President

                                       -8-




                              KEYBANK NATIONAL ASSOCIATION,
                              individually and as Documentation Agent


                              By: /s/ MARY ELLEN FOWLER
                                  ---------------------------------
                                    Its: Vice President


                              DRESDNER BANK AG, New York Branch and Grand Cayman
                              Branch, individually and as Co-Agent


                              By: /s/ CHRISTOPHER E. SARISKY
                                  ---------------------------------
                                    Its: Assistant Vice President

                              Attest: /s/ BEVERLY G. CARSON
                                      -----------------------------
                                         Its:


                              THE LONG-TERM CREDIT BANK OF JAPAN, LTD., LOS
                              ANGELES AGENCY


                              By: /s/ BRIAN H. KELLEY
                                  ---------------------------------
                                    Its: Deputy General Manager


                              CRESTAR BANK


                              By: /s/ GREGORY T. HORSTMAN
                                  ---------------------------------
                                    Its: Vice President


                              RIGGS BANK, N.A.


                              By:
                                  ---------------------------------
                                    Its:


                                       -9-




                              SUMMIT BANK


                              By: [ILLEGIBLE]
                                  ---------------------------------
                                    Its: Regional Vice President


                              FIRST AMERICAN BANK TEXAS, S.S.B.


                              By: /s/ JEFFREY SCHULTZ
                                  ---------------------------------
                                    Its: Vice Presient


                              SOVEREIGN BANK


                              By: /s/ THOMAS W. NADEAU
                                  ---------------------------------
                                    Its: Senior Vice President


                              THE INDUSTRIAL BANK OF JAPAN, LIMITED, LOS ANGELES
                              AGENCY


                              By: [ILLEGIBLE]
                                  ---------------------------------
                                    Its: Vice President


                              NATIONSBANK, N.A.


                              By: /s/ DONALD H. MOSES
                                  ---------------------------------
                                    Its: Senior Vice President


                              CEDARS BANK


                              By: [ILLEGIBLE]
                                  ------------------------------------
                                    Its: Senior Vice President, C.E.O.

                                       -10-



                              ADDITIONAL BORROWERS:

                              ARE-5 TRIANGLE DRIVE, LLC
                              ARE-50 WEST WATKINS MILL, LLC
                              ARE-100 PHILLIPS PARKWAY, LLC
                              ARE-279 PRINCETON ROAD, LLC
                              ARE-2001 ALICEANNA STREET, LLC
                              ARE-3770 TANSY STREET, LLC
                              ARE-10505 ROSELLE STREET, LLC

                              By:  Alexandria Real Estate Equities, L.P., their
                                   sole member

                                   By:  ARE-QRS Corp., a Maryland corporation,
                                        its general partner



                                        By: /s/ PETER J. NELSON
                                            ----------------------------------
                                            Name: Peter J. Nelson
                                            Title: Senior Vice President &
                                                   Chief Finanical Officer


                              ARE-60 WESTVIEW, LLC
                              ARE-377 PLANTATION STREET, LLC

                              By:  AREE-Holdings, L.P., a Delaware limited
                                   partnership, their managing member

                                   By:  ARE-GP Holdings QRS Corp., a Delaware
                                        corporation, its general partner



                                        By: /s/ PETER J. NELSON
                                            ----------------------------------
                                            Name: Peter J. Nelson
                                            Title: Senior Vice President &
                                                   Chief Finanical Officer

                                       -11-