Before the expiration of the period ending 18 months after the appointment of the Director under , any rules and regulations promulgated before , by the Secretary pursuant to the Federal National Mortgage Association Charter Act [ et seq.] or the Federal Home Loan Mortgage Corporation Act [ et seq.] shall remain in effect unless modified, terminated, superseded, or revoked by operation of law or in accordance with law. Such rules and regulations shall terminate, effective upon the expiration of such period.section 4512 of this title12 U.S.C. 171612 U.S.C. 1451October 28, 19921992-10-28