WordNet (r) 3.0 (2006):

regulatory
    adj 1: restricting according to rules or principles; "a
           regulatory gene" [syn: regulative, regulatory]

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "regulatory":
   ascendant, at the head, boss, chief, commanding, controlling,
   directing, directive, directorial, directory, dominant, general,
   governing, guiding, head, hegemonic, hegemonistic, in ascendancy,
   in charge, in chief, in the ascendant, leading, managerial,
   managing, master, paramount, predominant, predominate, prepollent,
   preponderant, preponderate, prepotent, prevalent, regnant,
   regulating, regulative, reigning, ruling, sovereign, supreme