<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

   
                                 FORM 10-Q/A

                               AMENDMENT NO. 1
    

(Mark One)
[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
        EXCHANGE ACT OF 1934

For the quarterly period ended March 31, 1997

                                       or

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
        EXCHANGE ACT OF 1934


                        Commission File Number: 333-13791


                               ENRON OREGON CORP.
             (Exact name of registrant as specified in its charter)

            Oregon                                          76-0511381
 (State or other jurisdiction of                         (I.R.S. Employer
  incorporation or organization)                         Identification No.)


                Enron Bldg.
             1400 Smith Street
               Houston, Texas                                  77002
  (Address of principal executive offices)                  (Zip code)

                                 (713) 853-6161
              (Registrant's telephone number, including area code)


      Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                       [X] Yes                            [ ] No

      As of March 31, 1997 there were 1,000 shares of common stock outstanding,
each of which was owned by the registrant's parent, Enron Corp.


                               Page 1 of 5 Pages
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                               ENRON OREGON CORP.

                                    FORM 10-Q

                                      INDEX

                                                                       Page No.
                                                                       --------
PART I  -  FINANCIAL INFORMATION

ITEM 1.        Financial Statements (see Note below)                       3

ITEM 2.        Management's Discussion and Analysis of Financial 
               Condition and Results of Operations (see Note below)        3


PART II  -  OTHER INFORMATION

ITEM 1.        Legal Proceedings                                           3

ITEM 2.        Changes in Securities                                       3

ITEM 3.        Defaults upon Senior Securities                             4

ITEM 4.        Submission of Matters to a Vote of Security Holders         4

ITEM 6.        Exhibits and Reports on Form 8-K                            4


SIGNATURES                                                                 5

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Part I         Financial Information

Item 1.        Financial Statements (see Note below)

Item 2.        Management's Discussion and Analysis of Financial Condition and 
               Results of Operations (see Note below)

      NOTE: Enron Oregon Corp. (the "Company" or "New Enron") was incorporated
under the laws of the State of Oregon on July 19, 1996 as a wholly owned
subsidiary of Enron Corp. ("Enron"). The Company was formed solely for the
purpose of effecting the transactions contemplated by the Amended and Restated
Agreement and Plan of Merger dated as of July 20, 1996 and amended and restated
as of September 24, 1996, as amended by the First Amendment thereto dated as of
April 14, 1997 (the "Merger Agreement") among Enron, the Company and Portland
General Corporation, an Oregon corporation ("PGC").

      Under the Merger Agreement, and subject to the terms and conditions
thereof, (i) Enron will be reincorporated as an Oregon corporation by merging
with and into New Enron (the "Reincorporation Merger") and (ii) immediately
thereafter, PGC will merge with and into New Enron, with New Enron being the
surviving corporation (the "PGC Merger" and, together with the Reincorporation
Merger, the "Mergers"). The Merger Agreement provides that if certain regulatory
reforms are enacted, the structure of the transactions contemplated by the
Merger Agreement will be revised to eliminate the Reincorporation Merger.

      Completion of the Mergers remains subject to approval by the PGC
shareholders on or about June 24, 1997, and satisfaction of regulatory approvals
and other customary closing conditions, including approval by the Oregon Public
Utility Commission.

      As a result, New Enron has not issued any of its authorized shares, except
for 1,000 shares of Common Stock issued to Enron in connection with the
formation of New Enron. Furthermore, New Enron has no assets, liabilities or
equity as of March 31, 1997 (or as of the date hereof), except for immaterial
amounts of cash contributed by Enron in connection with the formation of New
Enron. In addition, New Enron has conducted no operations and has incurred no
liabilities.

      Accordingly, there are no financial statements or Management's Discussion
and Analysis of Financial Condition and Results of Operations in this report.

      Upon the consummation of the Mergers, the assets, liabilities and equity
of Enron and PGC will become assets, liabilities and equity of New Enron and
will be included in New Enron's financial statements.

Part II        Other Information

Item 1.        Legal Proceedings

               None.

Item 2.        Changes in Securities

               As contemplated by the Merger Agreement, the Articles of
Incorporation of New Enron were amended and restated on October 7, 1996.
However, because Enron is the only shareholder of New Enron, and will be the
only shareholder until the consummation of the Mergers, the amendments will not
affect any security holder (other than Enron) until the Mergers have been
consummated. The Restated Articles of Incorporation are filed as Exhibit 3.1 to
this Quarterly Report and are incorporated by reference herein.


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               Furthermore, the forms of Series Designation for the New Enron
Cumulative Second Preferred Stock and 9.142% Perpetual Second Preferred Stock
are attached to this Quarterly Report as Exhibits 3.3 and 3.4, respectively, and
are incorporated by reference herein. However, such series designations have not
yet been adopted by the New Enron Board of Directors or filed with the Secretary
of State of the State of Oregon.

Item 3.        Defaults upon Senior Securities

               None.

Item 4.        Submission of Matters to a Vote of Security Holders

               None.

Item 6.        Exhibits and Reports on Form 8-K

      (a)      Exhibits.

      2.1      Amended and Restated Agreement and Plan of Merger dated as of
               July 20, 1996 and amended and restated as of September 24, 1996
               among Enron, New Enron and PGC (incorporated by reference to
               Exhibit 2.1 to New Enron's Registration Statement on Form S-4,
               Registration No. 333-13791).

      2.2      First Amendment to Amended and Restated  Agreement and Plan of 
               Merger, dated as of April 14, 1997, by and among Enron, New 
               Enron and PGC.

      3.1      Restated Articles of Incorporation of New Enron (incorporated by
               reference to Exhibit 3.1 to New Enron's Registration Statement 
               on Form S-4, Registration No. 333-13791).

      3.2      Form of Bylaws of New Enron (incorporated by reference to 
               Exhibit 3.2 to New Enron's Registration Statementon Form S-4,
               Registration No. 333-13791).

      3.3      Form of Series Designation for the New Enron Cumulative Second 
               Preferred Convertible Stock (incorporated by reference to
               Exhibit 3.3 to New Enron's Registration Statement on Form S-4, 
               Registration No. 333-13791).

      3.4      Form of Series Designation for the New Enron 9.142% Perpetual 
               Second Preferred Stock (incorporated  by reference to Exhibit 
               3.4 to New Enron's Registration Statement on Form S-4, 
               Registration No. 333-13791).

     27        Financial Data Schedule.

      (b)      Reports on Form 8-K.

               None.


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                                   SIGNATURES

      Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this amended report to be signed on its behalf by the
undersigned thereunto duly authorized.

                                           ENRON OREGON CORP.


Date:  May 14, 1997                        By: /s/ William D. Gathmann
                                              -------------------------------
                                           Name:  William D. Gathmann
                                           Title: Vice President, Finance and
                                                  Treasurer
                                                  (Principal Financial Officer)





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                                  EXHIBIT INDEX

   
      2.2 --   First Amendment to Amended and Restated  Agreement and Plan of 
               Merger, dated as of April 14, 1997, by and among Enron, New 
               Enron and PGC.
    

     27   --   Finanacial Data Schedule