Exhibit 10.3

Loan No. 1686410

GUARANTY

     THIS GUARANTY (the “Guaranty”) is made as of September 25, 2003, by
NEUROCRINE BIOSCIENCES, INC., a Delaware corporation (“Guarantor”), with
reference to the facts set forth below.

     A.     SAN DIEGO NATIONAL BANK, a national banking association (“Lender”),
has entered into a Construction Loan Agreement of even date herewith (the “Loan
Agreement”), with SCIENCE PARK CENTER LLC, a California limited liability
company (“Borrower”). (Except as otherwise provided in this Guaranty, terms with
initial capital letters herein shall have the same meanings as set forth in the
Loan Agreement.)

     B.     Pursuant to the Loan Agreement, Lender will make to Borrower a loan
in an original amount not to exceed the principal sum of up to $60,600,000.00
(“Loan”). The Loan is to be used by Borrower to construct certain improvements
on the Property described in the Loan Agreement, and is to be secured by the
Property. The Loan is to be evidenced and secured by the Note and the other Loan
Documents.

     C.     As an essential inducement of the making of the Loan and in
consideration therefor, Guarantor has agreed to execute this Guaranty. The
obligations guarantied pursuant to Section 1 below are referred to collectively
herein as the “Guarantied Obligations”.

     D.     Guarantor will obtain substantial direct and indirect benefits from
the making of the Loan.

     NOW, THEREFORE, in consideration of the premises, and to induce and in
consideration for the making of the Loan, Guarantor agrees as set forth below.

     1.     Guaranty.

               1.1   Guarantor hereby unconditionally and irrevocably guaranties
to Lender the full and prompt payment and performance of all indebtedness and
obligations, of any nature whatsoever, of Borrower under the Note and all other
Loan Documents and any and all extensions, renewals, substitutions,
replacements, and modifications thereof, whether now in existence or hereafter
created, including, without limitation, (a) all principal of and interest on the
Note and (b) all fees, charges, costs, and other amounts payable by Borrower
under the Note and other Loan Documents (all of the foregoing obligations
collectively, the “Guarantied Obligations”).

               1.2   This is a guaranty of all Guarantied Obligations,
including, without limitation, obligations and liabilities arising under
successive and future transactions that either increase, decrease, or continue
the Guarantied Obligations, or, from time to time, renew Guarantied Obligations
that have been satisfied, independent of and in addition to any guaranty,
endorsement, or collateral now or hereafter held by Lender, whether or not
furnished by Guarantor. This Guaranty shall be irrevocable, and Guarantor waives
any right to revoke this Guaranty and the benefits of California Civil Code
Section 2815.

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     2.     Rights of Lender. Guarantor authorizes Lender at any time in its
sole discretion to take any of the following actions on such terms and
conditions as Lender may elect, without giving notice to Guarantor or any other
person or obtaining the consent of Guarantor or any other person and without
affecting Guarantor’s obligations under this Guaranty:

               2.1   Alter any of the terms and(or) documentation of any of the
Guarantied Obligations or Loan Documents, including renewing, amending,
releasing, waiving, compromising, extending or accelerating, or otherwise
changing the time for payment of, or increasing or decreasing the Guarantied
Obligations or the rate of interest on, the Guarantied Obligations;

               2.2   accept new or additional documents, instruments or
agreements relative to the Guarantied Obligations;

               2.3   consent to the change, restructure or termination of the
individual, partnership, limited liability company, corporate or other
organizational structure or existence of Borrower, Guarantor or any other person
or any affiliate of Borrower, Guarantor or any other person, and correspondingly
restructure the Guarantied Obligations;

               2.4   accept partial payments on the Guarantied Obligations;

               2.5   take and hold any security or additional guaranties for the
Guarantied Obligations and amend, alter, exchange, substitute, transfer,
enforce, perfect or fail to perfect, waive, subordinate, terminate, compromise,
or release any such security or guaranties;

               2.6   apply any security, and direct the order and manner of sale
thereof as Lender in its sole discretion may determine;

               2.7   settle, release on terms satisfactory to Lender or by
operation of law or otherwise, compound, compromise, collect or otherwise
liquidate the Guarantied Obligations and(or) the security or any guaranty
therefor in any manner;

               2.8   release Borrower or any other person of its liability for
all or any of the Guarantied Obligations;

               2.9   participate in any settlement offered by Borrower, any
guarantor or any other person, whether in liquidation, reorganization,
receivership, bankruptcy, assignment for the benefit of creditors or other
debtor-relief proceeding or otherwise;

               2.10   exercise or not exercise rights available to it in any
liquidation, reorganization receivership, bankruptcy, assignment for benefit of
creditors or other debtor-relief proceeding, including voting or not voting to
accept a plan and filing or not filing a proof of claim;

               2.11   release, substitute or add any one or more guarantors or
endorsers; and

               2.12   assign its rights under this Guaranty in whole or in part.

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     3.     Independent Obligations. Guarantor shall pay to (in immediately
available funds) and perform for the benefit of Lender, when due, on demand of
Lender, all Guarantied Obligations. This Guaranty is a guaranty of payment and
performance and not of collectability. Guarantor’s obligations under this
Guaranty are independent of those of Borrower and those of any other guarantor
or other person. Lender may bring a separate action against Guarantor without
proceeding against Borrower or any other guarantor or other person or any
security held by Lender and without pursuing any other remedy.

     4.     Waiver of Defenses. Guarantor waives and agrees not to assert or
take advantage of:

               4.1   Any right to require Lender to proceed against Borrower,
any other guarantor or any other person or any security now or hereafter held by
Lender or to pursue any other remedy whatsoever, including any such right or any
other right set forth in or arising out of Sections 2845, 2848, 2849, 2850, 2899
or 3433 of the California Civil Code;

               4.2   any defense based upon any legal disability of Borrower or
any guarantor or other person, or any discharge or limitation of the liability
of Borrower or any guarantor or other person to Lender (except on satisfaction
of all of Borrower’s obligations with respect to the Loan and Loan Documents),
or any restraint or stay applicable to actions against Borrower or any guarantor
or other person, whether such disability, discharge, limitation, restraint or
stay is consensual, or arising by order of a court or other Governmental
Authority, or arising by operation of law or any liquidation, reorganization,
insolvency, receivership, bankruptcy, assignment for the benefit of creditors or
other debtor-relief proceeding, whether or not Lender consents to such treatment
in such proceeding, or from any other cause, including any defense to the
payment of interest, attorneys’ fees and costs, and other charges that otherwise
would accrue or become payable in respect to the Guarantied Obligations after
the commencement of any such proceeding;

               4.3   setoff, counterclaim, presentment, demand, protest, notice
of protest, notice of nonpayment, or other notice of any kind;

               4.4   any defense based upon the modification, renewal, extension
or other alteration of any of the Guarantied Obligations, or of the documents
executed in connection therewith;

               4.5   any defense based upon the negligence of Lender, including
the failure to record an interest under a deed of trust, the failure to perfect
any security interest, or the failure to file a claim in any bankruptcy of
Borrower or any guarantor or other person;

               4.6   any defense based upon a statute of limitations to the
fullest extent permitted by law and any defense based upon Lender’s delay in
enforcing this Guaranty or any other agreement;

               4.7   all rights of subrogation, reimbursement, indemnity and
contribution, all rights to enforce any remedy that Lender may have against
Borrower or other person, and all rights to participate in any security held by
Lender for the Guarantied Obligations, including any such right or any other
right set forth in Sections 2848 or 2849 of the California Civil Code, until

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the Guarantied Obligations have been paid and performed in full, and any defense
based upon the impairment of any subrogation, reimbursement, indemnity or
contribution rights that Guarantor might have, including any defense or right
based upon the acceptance by Lender or an affiliate of Lender of a deed in lieu
of foreclosure without extinguishing the Guarantied Obligations, even if such
acceptance destroys, alters or otherwise impairs subrogation rights of
Guarantor, the right of Guarantor to proceed against Borrower or any other
person for reimbursement, or both;

               4.8   any defense based upon or arising out of any defense which
Borrower or any other guarantor or other person may have to the performance of
any part of the Guarantied Obligations;

               4.9   any defense to recovery by Lender of a deficiency after
non-judicial foreclosure sale of real or personal property; any defense based
upon unavailability to Lender of a deficiency judgment after nonjudicial sale of
real or personal property; and any defense based upon or arising out of any of
Sections 580a (which might limit the amount of any deficiency judgment which
might be recoverable following the occurrence of a trustee’s sale under a deed
of trust), 580b and 580d (which may limit the right to recover a deficiency
judgment with respect to purchase money obligations and after a non-judicial
foreclosure sale, respectively), or 726 (which, among other things, may require
the exhaustion of security before a personal judgment may be obtained for a
deficiency) of the California Code of Civil Procedure (including but not limited
to any fair value limitations under Sections 580a or 726 of such Code) or based
upon or arising out of Divisions 8 or 9 or other applicable divisions of the
California Uniform Commercial Code;

               4.10   any defense based upon the death, incapacity, lack of
authority or termination of existence of, or purported revocation or rescission
of this Guaranty or any of the Guarantied Obligations by, any person, or the
substitution of any party hereto or thereto;

               4.11   any defense based upon or related to Guarantor’s lack of
knowledge as to Borrower’s financial condition;

               4.12   any right to revoke this Guaranty or obligations hereunder
and all rights and benefits of Section 2815 of the California Civil Code;

               4.13   any right to designate the application of any sums or
property received by Lender, and in connection therewith, Guarantor agrees that
any amounts or sums received by Lender from any source on account of the
Guarantied Obligations may be applied by Lender toward payment thereof in such
order of application as Lender may from time to time elect, notwithstanding any
contrary designation by Borrower, Guarantor or any other person;

               4.14   any defense based upon any action taken or omitted by
Lender in any bankruptcy or other insolvency proceeding involving Borrower or
any other person, including any election to have Lender’s claim allowed as
secured, partially secured or unsecured, any extension of credit by Lender to
Borrower in any such proceeding, and the taking and holding by Lender of any
security for any such extension of credit; and

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               4.15   any right or defense that is or may become available to
Guarantor by reason of California Civil Code Sections 2787 to and including
2855, 2899 and 3433.

     5.     Borrower’s Financial Condition. Guarantor acknowledges that it is
relying upon its own knowledge of and is fully informed with respect to
Borrower’s financial condition. Guarantor assumes full responsibility for
keeping fully informed of Borrower’s financial condition and all other
circumstances affecting Borrower’s ability to perform the Guarantied
Obligations, and agrees that Lender will have no duty to report to Guarantor any
information which Lender receives about Borrower’s financial condition or any
circumstances bearing on Borrower’s ability to perform all or any portion of the
Guarantied Obligations, regardless of whether Lender has reason to believe that
any such facts materially increase the risk beyond that which Guarantor intends
to assume or has reason to believe that such facts are unknown to Guarantor or
has a reasonable opportunity to communicate such facts to Guarantor.

     6.     Impairment of Subrogation Rights.

               6.1   Upon a default of Borrower or an Event of Default, Lender
may elect to foreclose nonjudicially or judicially against any real or personal
property security it holds for any of the Guarantied Obligations, exercise any
other remedy against Borrower or any security or any guarantor or other person,
and(or) take a deed or assignment of security in lieu of foreclosure. No such
action by Lender will release or limit the liability of Guarantor, even if the
effect of that action is to deprive Guarantor of the right or ability to collect
reimbursement from or assert subrogation, indemnity or contribution rights
against Borrower or any other guarantor or other person for any sums paid to
Lender, or to obtain reimbursement by means of any security held by Lender for
the Guarantied Obligations.

               6.2   Guarantor acknowledges that if Lender elects to foreclose
nonjudicially against any real property security it holds for the Guarantied
Obligations or any part thereof, Guarantor may have subrogation rights that
might be destroyed by virtue of application of Section 580d of the California
Code of Civil Procedure and will or may have a defense to its liability under
this Guaranty. Without in any way limiting any other waiver, consent or
acknowledgment contained in this Guaranty and in addition thereto, Guarantor
hereby waives and agrees not to assert or take advantage of any defense based
upon such Section 580d of the California Code of Civil Procedure or any loss or
impairment of subrogation or other rights against Borrower or any other person
or entity, and no such nonjudicial foreclosure by Lender shall release or limit
the liability of Guarantor under this Guaranty.

               6.3   Guarantor waives all rights and defenses arising out of an
election of remedies by Lender, even though that election of remedies, such as
nonjudicial foreclosure with respect to security for the Guarantied Obligations,
has destroyed Guarantor’s rights of subrogation and(or) reimbursement against
Borrower or other person by the operation of Section 580d of the California Code
of Civil Procedure or otherwise.

               6.4   Guarantor waives all rights and defenses arising out of the
operation of Section 580a of the California Code of Civil Procedure, and further
waives its right to a fair value hearing under such Section 580a to determine
the size of a deficiency judgment following any foreclosure sale on encumbered
real property.

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               6.5   Guarantor waives all rights and defenses that Guarantor may
have because the Guarantied Obligations are secured by real property. This
means, among other things: (a) Lender may collect from Guarantor without first
foreclosing on any real or personal property collateral pledged by Borrower or
otherwise; and (b) if Lender forecloses on any real property collateral, (i) the
amount of the Guarantied Obligations may be reduced only by the price for which
that collateral was sold at the foreclosure sale, even if the collateral is
worth more than the sale price and (ii) Lender may collect from Guarantor even
if Lender, by foreclosing on the real property collateral, has destroyed any
right Guarantor may have to collect from Borrower or other person. This is an
unconditional and irrevocable waiver of any rights and defenses Guarantor may
have because the Guarantied Obligations or portions thereof are secured by real
property. These rights and defenses include, but are not limited to, any rights
or defenses based upon Sections 580a, 580b, 580d, or 726 of the California Code
of Civil Procedure.

     7.     Security Interest. Guarantor grants to Lender a security interest in
all moneys, securities and other property of Guarantor now or hereafter in
Lender’s possession, and all present and future deposit accounts of Guarantor
with Lender to secure Guarantor’s performance hereunder.

     8.     Default. Each of the following shall constitute a default of
Guarantor under this Guaranty, entitling Lender, at its option and in addition
to its other remedies, to accelerate all of Guarantor’s Obligations hereunder
and to collect immediately from Guarantor the full amount of the Guarantied
Obligations:

               8.1   The failure of Guarantor to perform any of its obligations
under this Guaranty;

               8.2   the commencement of any liquidation, reorganization,
receivership, bankruptcy, assignment for the benefit of creditors or other
debtor-relief proceeding by Borrower or Guarantor;

               8.3   any representation or warranty made by Guarantor hereunder
shall be false in any material respect;

               8.4   Guarantor shall fail to comply with any of the other terms
or provisions of this Guaranty;

               8.5   the occurrence of an Event or Default under any of the
other Loan Documents; and

               8.6   the revocation or purported revocation by Guarantor of this
Guaranty.

     9.     Bankruptcy.

               9.1   The obligations of Guarantor under this Guaranty shall not
be altered, limited, or affected by any proceeding, voluntary or involuntary,
involving the bankruptcy, insolvency, receivership, reorganization, liquidation,
or arrangement of Borrower, or by any defense Borrower may have by reason of any
order, decree, or decision of any court or administrative body resulting from
any such proceeding. In furtherance of the foregoing,

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Guarantor agrees that if acceleration of the time for payment of any amount
payable by Borrower under the Note or in respect of the other Guarantied
Obligations is stayed for any reason, all such amounts otherwise subject to
acceleration shall nonetheless be payable by Guarantor hereunder forthwith upon
demand.

               9.2   Guarantor shall file in any bankruptcy or other proceeding
in which the filing of claims is required or permitted by law all claims that
Guarantor may have against Borrower relating to any indebtedness of Borrower to
Guarantor, and will assign to Lender all rights of Guarantor thereunder. If
Guarantor does not file any such claim at least ten (10) days prior to any
deadline thereof, then to the extent allowed by law, Lender, as attorney-in-fact
for Guarantor, is hereby authorized to do so in the name of Guarantor or, in
Lender’s discretion, to assign the claim to a nominee, and to cause such proof
of claim to be filed in the name of Lender’s nominee. The foregoing power of
attorney is coupled with an interest and is irrevocable until after the
indefeasible payment and performance in full of all of the Guarantied
Obligations. In all such cases, whether in administration, bankruptcy, or
otherwise, the person or persons authorized to pay such claim shall pay to
Lender the amount payable on such claim. Guarantor hereby assigns to Lender all
of Guarantor’s rights to any such payments or distributions to which Guarantor
would otherwise be entitled; provided, however, that Guarantor’s obligations
hereunder shall not be satisfied except to the extent that Lender receives cash
by reason of any such payment or distribution. If Lender receives anything
hereunder other than cash, the same shall be held as collateral for amounts due
under this Guaranty.

     10.     Continuance of Guaranty. The liability of Guarantor hereunder shall
continue in effect notwithstanding any payment or performance of the Guarantied
Obligations by Borrower, such that, if any such payment or performance is
avoided or recovered from Lender or Lender is otherwise required to restore or
return any such payment or performance in connection with the bankruptcy,
insolvency or reorganization of Borrower or otherwise, Guarantor shall remain
liable hereunder as though such payment or performance had not occurred. The
determination as to whether any such payment or performance must be restored or
returned may be made by Lender in its sole discretion; provided, however, that
if Lender chooses in its discretion to contest any such matter, Guarantor agrees
to indemnify, defend and hold harmless Lender from all costs and expenses
(including, without limitation, legal fees and disbursements) of such
litigation. Lender shall be under no obligation to return or deliver this
Guaranty to Guarantor, notwithstanding the payment or performance of the
Guarantied Obligations. If this Guaranty is nevertheless returned to Guarantor
or is otherwise released, then the provisions herein shall survive such return
or release, and the liability of Guarantor under this Guaranty shall survive
such return or release, and Guarantor shall remain liable under this Guaranty
under the circumstances provided herein notwithstanding such return or release.

     11.     Subordination.

               11.1   All existing and future obligations of Borrower to
Guarantor (including, without limitation, any obligations arising by reason of
any payment by Guarantor hereunder) are hereby subordinated to the full and
indefeasible payment and performance of the Guarantied Obligations.

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               11.2   Upon any default under any of the Guarantied Obligations
or hereunder, all obligations of Borrower to Guarantor shall be collected,
enforced and received by Guarantor as trustee for Lender, and all amounts
received shall be paid over to Lender, for application to the Guarantied
Obligations. In the event of a bankruptcy case against Borrower, Lender shall,
at its option, be entitled to file a proof of claim on behalf of Guarantor under
the Bankruptcy Rule 3001. Lender shall be entitled to all voting rights and
distributions on account of such claim until full and complete performance of
the Guaranteed Obligations.

     12.     Representations and Warranties. Guarantor represents and warrants
as follows:

               12.1   Guarantor is a corporation duly incorporated, validly
existing, and is in good standing under the laws of the jurisdiction of its
incorporation and is duly qualified to do business in Delaware, California and
all other states, if any, in which it is required to be qualified;

               12.2   Guarantor has the requisite power and authority to own and
manage its properties, to carry on its business as now being conducted and to
perform its obligations hereunder;

               12.3   The individual(s) executing this Guaranty on behalf of
Guarantor or any person comprising a part of Guarantor is authorized and
empowered by his/her or their signatures alone to bind Guarantor;

               12.4   Guarantor has the full right, power and authority to
execute and deliver this Guaranty and any other Loan Document to be executed and
delivered by it, consummate the transactions contemplated hereby and thereby,
and perform its obligations hereunder and thereunder. This Guaranty and the
other Loan Documents to be executed and delivered by Guarantor have been duly
authorized, executed and delivered, and do not and will not require any consent
or approval of any person or entity other than that which has been heretofore
obtained;

               12.5   Guarantor is in compliance with all laws, regulations,
ordinances and orders of public authorities applicable to it;

               12.6   The execution, delivery and performance by Guarantor of
this Guaranty (a) have been duly authorized by all necessary action, (b) are
within the power of Guarantor, (c) have received all necessary governmental
approvals, and (d) do not and will not (i) contravene Guarantor’s corporate
charter, bylaws, or any other of Guarantor’s Organizational Documents,
(ii) violate any provision of any law, rule or regulation or any order, judgment
or decree of any court or agency of government, or any indenture, agreement or
any other instrument to which Guarantor is a party or by which Guarantor or its
property is bound, (iii) result in a breach of or constitute (with due notice
and(or) lapse of time) a default under any such indenture, agreement or other
instruments, (iv) result in the creation or imposition of any lien, charge or
encumbrance of any nature whatsoever under any agreement, mortgage, deed of
trust, lease, loan or security agreement, partnership agreement, corporate
charter, bylaws or other document, agreement or instrument to which Guarantor is
a party or by which it or its property or assets may be bound or affected; and
Guarantor is not in default under any such law, rule, regulation, order,
judgment, decree, indenture, agreement or instrument;

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               12.7   This Guaranty has been duly executed by Guarantor and,
when delivered to Lender, will constitute a legal, valid and binding obligation
enforceable against Guarantor in accordance with its terms, except to the extent
that enforceability may be limited by applicable bankruptcy, insolvency,
moratorium, reorganization or other similar laws affecting the enforcement of
creditors’ rights or by the effect of general equitable principles;

               12.8   All financial statements and data that have been given to
Lender by Guarantor with respect to Guarantor (a) are complete and correct in
all material respects as of the date given; (b) accurately present the financial
condition of Guarantor on each date as of which, and the results of Guarantor’s
operations for the periods for which, the same have been furnished; and (c) have
been prepared in accordance with GAAP consistently applied throughout the
periods covered thereby;

               12.9   All balance sheets and the notes thereto with respect to
Guarantor furnished to Lender disclose all material liabilities of Guarantor,
fixed and contingent, as of their respective dates;

               12.10   There has been no material adverse change in the
financial condition or operations of Guarantor since (a) the date of the most
recent financial statement given to Lender with respect to Guarantor, or (b) the
date of the financial statements given to Lender immediately prior to the date
hereof, other than changes in the ordinary course of business, none of which
changes has been materially adverse individually or in the aggregate;

               12.11   All other reports, papers and written data and
information given to Lender by Guarantor with respect to Guarantor are accurate
and correct in all material respects;

               12.12   To the best of Guarantor’s knowledge, Guarantor is not in
material default in the performance, observance or fulfillment of any of the
obligations, covenants or conditions set forth in any material agreement or
instrument to which Guarantor is a party;

               12.13   Except as disclosed to Lender in writing and approved by
Lender, there is not now pending against or affecting Guarantor, nor to the
knowledge of Guarantor is there threatened, any action, suit or proceeding at
law or in equity or by or before any administrative agency that, if adversely
determined, would materially impair or affect the financial condition or
operations of Guarantor; Guarantor is not in default with respect to any order,
writ, injunction, decree or demand of any court or any Governmental Authority;

               12.14   Guarantor has filed all federal, state, provincial,
county, municipal and other income tax returns legally required to have been
filed by Guarantor and has paid all taxes that have become due pursuant to such
returns or pursuant to any assessments received by Guarantor, and Guarantor does
not know of any basis for any material additional assessment against it in
respect of such taxes;

               12.15   Guarantor is not insolvent, and will not be rendered
insolvent hereunder, and no bankruptcy or insolvency proceedings are pending or
to the best of Guarantor’s knowledge contemplated by or against Guarantor;

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               12.16   Guarantor represents and warrants to Lender that the Loan
benefits Guarantor;

               12.17   The value of the consideration received and to be
received by Guarantor in connection with the Guarantied Obligations or
transactions contemplated thereby is reasonably worth at least as much as the
liability and obligations of Guarantor incurred or arising under this Guaranty.
Guarantor has had full and complete access to the Loan Agreement, the Note, the
Deed of Trust and all other Loan Documents relating to the Guarantied
Obligations, has reviewed them and is fully aware of the meaning and effect of
their contents. Guarantor is fully informed of all circumstances which bear upon
the risks of executing this Guaranty and which a diligent inquiry would reveal.
Guarantor has adequate means to obtain from Borrower on a continuing basis
information concerning Borrower’s financial condition, and is not depending on
Lender to provide such information, now or in the future. Guarantor agrees that
Lender shall not have any obligation to advise or notify Guarantor or to provide
Guarantor with any data or information;

               12.18   Guarantor has all requisite power and authority to
transact any other business with Lender as necessary to fulfill the terms of
this Guaranty; and

               12.19   Guarantor and Borrower are not the alter ego of the
other.

     13.     Covenants. Guarantor agrees that, so long as any part of the
Guarantied Obligations shall remain to be performed or paid, Guarantor will,
unless Lender shall otherwise consent in writing:

               13.1   File all federal, state, provincial, county, municipal and
other income tax returns required to be filed by it and pay before the same
become delinquent all taxes that become due pursuant to such returns or pursuant
to any assessments received by it, except such taxes as are being contested in
good faith by appropriate proceedings;

               13.2   Promptly and faithfully comply with all laws, ordinances,
rules, regulations and requirements, both present and future, of every duly
constituted Governmental Authority or agency having jurisdiction that may be
applicable to it or its property or assets;

               13.3   Maintain full and complete books of account and other
records reflecting the results of its operations, and furnish to Lender such
information about the financial condition and operations of Guarantor as Lender
shall reasonably request, including, but not limited to, the following
information which shall be furnished without request: (a) copies of filed tax
returns and annual operating statements, balance sheets, statements of changes
in financial position and related notes and such other financial statements and
reports in such form and content as Lender may require on or before 120 days
following the end of each applicable fiscal year, which financial statements may
be internally prepared and certified under penalty of perjury to Lender by an
authorized member of senior management; (b) copies of all project-specific
financial statements, reports and notices delivered by Borrower or any of its
members on its behalf to Guarantor as provided in any of Borrower’s
Organizational Documents; (c) copies of interim operating statements, balance
sheets, statements of change of financial position and such other financial
reports as Lender may require on or before the tenth (10th) Business Day
following Lender’s demand; and (d) such other information, report or data as
Lender may reasonably

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request; provided so long as the Guarantor is subject to the reporting
provisions of the Securities Exchange Act, as amended (the “Exchange Act”), the
timely filing (including all permissible extension periods provided under Rule
12b-25 under the Exchange Act) on the Securities and Exchange Commission’s EDGAR
system of the Guarantor’s quarterly report on Form 10-Q for such period and
annual report on Form 10-K for such period will be deemed to satisfy all of the
foregoing requirements of this Section 13.3.

               13.4   Take all steps necessary to maintain its existence and
continue to be in good standing in the state of its incorporation and remain
qualified to do business in the State of California;

               13.5   Except as approved in writing by Lender, Guarantor shall
not incur indebtedness or other liabilities if the same will or is reasonably
likely to have a material adverse effect upon the financial condition or
operations of Guarantor; and

               13.6   Guarantor shall not, without Lender’s prior written
consent which shall not be unreasonably withheld: (a) amend, modify or change
any of its Organizational Documents; (b) change its fiscal year; or (c) change
its principal place of business, name, organizational identity, organizational
structure or state of organization.

     14.     Costs and Expenses. In the event Lender takes any action to enforce
the Guarantied Obligations or this Guaranty, either by legal proceedings or
otherwise, Lender shall be reimbursed immediately by Guarantor for
reasonably-incurred attorneys’ fees (including fees for Lender’s in-house
attorneys) and other costs and expenses. Guarantor shall also immediately
reimburse Lender for all attorneys’ fees and costs reasonably incurred in
connection with the representation of Lender in any liquidation, reorganization,
receivership, bankruptcy, assignment for the benefit of creditors or other
debtor-relief proceeding of or relating to Borrower, Guarantor, or the Property.
Until paid to Lender, all such sums will bear interest from the date incurred at
the rate set forth in the Note.

     15.     Delay; Cumulative Remedies. No delay or failure by Lender to
exercise any right or remedy against Borrower or Guarantor or any other
guarantor or other person shall be construed as a waiver of that right or
remedy. All remedies of Lender against Borrower, Guarantor and any other person
are cumulative.

     16.     Severability. The invalidity or unenforceability of any one or more
provisions of this Guaranty will not affect the validity or enforceability of
any other provision.

     17.     Controlling Law; Venue; Interpretation.

               17.1   This Guaranty shall be governed by and construed in
accordance with the internal laws of the State of California, except to the
extent federal law applies. Venue for any action brought under this Guaranty
will be at Lender’s option, in the Superior Court of the State of California for
the County of San Diego. Guarantor hereby accepts for itself and in respect to
its property, generally and unconditionally, the exclusive jurisdiction of the
foregoing court. Guarantor irrevocably consents to the service of process in any
action or proceeding by the mailing of copies thereof by registered or certified
mail, postage prepaid, to Guarantor at its

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address for notices pursuant to this Guaranty. Nothing contained herein shall
affect the right of Lender to serve process in any other manner permitted by
law.

               17.2   As used herein, the terms “include,” “including” and forms
thereof are nonexclusive.

               17.3   As used herein, the term “day” means calendar day, except
when used in the defined term “Business Day.”

               17.4   As used herein, the term “person” means any individual,
corporation partnership, limited liability company, trust, Governmental
Authority, or other entity of any kind.

               17.5   Singular words shall connote the plural as well as the
singular and vice versa as the context requires.

               17.6   Each gender will include any other gender.

     18.     Binding Effect. The provisions of this Guaranty will bind and
benefit the heirs, executors, administrators, legal representatives, successors
and assigns of Guarantor and Lender. The term “Borrower” will mean both the
named Borrower and any other person or entity at any time assuming or otherwise
becoming primarily liable for all or any part of the Guarantied Obligations. The
term “Lender” will mean both Lender named herein and any future owner or holder,
including pledgees and participants, of the Note, or any interest therein.

     19.     Joint and Several Liability. The liability of multiple guarantors
is joint and several. If Guarantor is a partnership, such Guarantor and all
general partners therein shall be jointly and severally liable hereunder. Any
married person who executes this Guaranty agrees that recourse may be had
against his or her separate property.

     20.     Modification or Waiver. No provision of this Guaranty or Lender’s
rights hereunder can be waived or modified nor can Guarantor be released from
its obligations hereunder except by a writing executed by Lender. No such waiver
shall be applicable except in the specific instance for which given.

     21.     Entire Agreement. This Guaranty constitutes the entire agreement
between the parties with respect to its subject matter, and supersedes all prior
or contemporaneous agreements, representations and understandings. No supplement
to or modification of this Guaranty shall be binding unless executed in writing
by all the parties.

     22.     Headings. All headings in this Guaranty are for convenience in
reference only and do not define or limit the scope of provisions of this
Guaranty.

     23.     Notice. All notices, demands and other communications required or
permitted hereunder shall be in writing, addressed to the appropriate party as
its address appears below, or to such other address as may be designated from
time to time by notice to the other party in the manner set forth herein, and
shall be effective upon the earliest of (a) actual delivery if delivered by
personal delivery or certified postage-prepaid mail, (b) three (3) Business Days
following deposit, first class postage prepaid, with the United States Mail, or
(c) the next Business Day

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after timely and proper deposit with an overnight air courier with request for
delivery on the next Business Day.

     24.     Financial Reporting Requirements. Guarantor acknowledges that the
Loan Agreement requires that Lender be provided, upon demand, with reports and
other materials relating to Guarantor’s financial condition, including tax
returns, operating statements, balance sheets, statements of changes in
financial position, and such other financial statements and reports as Lender
may require. Guarantor agrees to provide such materials as specified in the Loan
Agreement except where the failure to do so would not result in a material
adverse effect.

     25.     WAIVER OF RIGHTS OF TRIAL BY JURY. EACH OF GUARANTOR AND LENDER (BY
ITS ACCEPTANCE HEREOF) HEREBY VOLUNTARILY, KNOWINGLY, INTENTIONALLY, IRREVOCABLY
AND UNCONDITIONALLY WAIVES ANY RIGHT TO HAVE A JURY PARTICIPATE (INCLUDING BY
WAY OF JURY TRIAL) IN RESOLVING ANY DISPUTE OR LITIGATION (WHETHER BASED UPON
CONTRACT, TORT OR OTHERWISE) BETWEEN OR AMONG GUARANTOR AND LENDER, ARISING OUT
OF OR IN ANY WAY RELATED TO THIS GUARANTY, THE LOAN, THE LOAN DOCUMENTS OR
ACTIONS OF GUARANTOR OR LENDER RELATING TO THE GUARANTY, LOAN AND(OR) THE
LENDING RELATIONSHIP WHICH IS THE SUBJECT OF THE LOAN DOCUMENTS OR THIS
AGREEMENT. THIS PROVISION AND THE WAIVER SET FORTH HEREIN ARE MATERIAL
INDUCEMENTS TO LENDER TO PROVIDE THE FINANCING DESCRIBED HEREIN AND IN THE LOAN
DOCUMENTS.

     26.     Counterparts. This Guaranty may be signed in counterparts, which
together shall constitute the agreement of the parties when each party has
signed a counterpart.

     27.     Secured Obligations. This Guaranty and the Guarantor’s performance
of its obligations hereunder are secured by that certain Security Agreement (the
“Security Agreement”), of even date herewith, executed by Guarantor in favor of
Lender. Reference is made to the Security Agreement for a specific description
of the security given to Lender by Guarantor thereunder.

     28.     Obligations Continue in Full Force and Effect. Borrower is
obligated to acquire the Property from Peony Acquisitions LLC, a Delaware
limited liability company (“Peony”), on or before November 26, 2003.
Notwithstanding Borrower’s acquisition of the Property and the assumption by
Borrower of certain obligations of Peony under certain Loan Documents securing
the Loan, all of Guarantor’s obligations hereunder will continue to remain in
full force and effect and for the benefit of Lender.

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     IN WITNESS WHEREOF, the undersigned has executed this Guaranty as of the
day and year first written above.

              GUARANTOR:                 NEUROCRINE BIOSCIENCES, INC.,     a
Delaware corporation               By:   /s/ Margaret Valeur-Jensen        

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    Name:   Margaret Valeur-Jensen        

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    Its:   Senior Vice President, Gen. Counsel & Secretary        

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    By:            

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    Name:            

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    Its:            

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              Address of Guarantor:               NEUROCRINE BIOSCIENCES, INC.  
  10555 Science Center Drive     San Diego, CA 92121     Attn: Paul Hawran      
        With a copy to:               Margaret E. Valeur-Jensen     NEUROCRINE
BIOSCIENCES, INC.     10555 Science Center Drive     San Diego, CA 92121        
      Address of Lender:               SAN DIEGO NATIONAL BANK     1420 Kettner
Boulevard     San Diego, California 92101     Attention: Jim Holliman

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        STATE OF CALIFORNIA   )       ) ss COUNTY OF SAN DIEGO   )  

     On            , before me,            , personally appeared
          personally known to me or proved to me on the basis of satisfactory
evidence to be the person whose name is subscribed to the within instrument and
acknowledged to me that executed the same in authorized capacity, and that by
signature on the instrument the person, or the entity upon behalf of which the
persons acted, executed the instrument.

        WITNESS my hand and official seal.                

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        STATE OF CALIFORNIA   )       ) ss COUNTY OF SAN DIEGO   )  

     On            , before me,            , personally appeared
          personally known to me or proved to me on the basis of satisfactory
evidence to be the person whose name is subscribed to the within instrument and
acknowledged to me that executed the same in authorized capacity, and that by
signature on the instrument the person, or the entity upon behalf of which the
persons acted, executed the instrument.

        WITNESS my hand and official seal.                

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