To provide a compound useful as a prophylactic or therapeutic agent for a sex hormone-dependent disease or the like. [MEANS FOR SOLVING PROBLEMS] Disclosed are: a nitrogenated fused ring derivative represented by the general formula (I), or a prodrug, salt or the like thereof, which has a GnRH antagonistic activity; a pharmaceutical composition comprising the derivative or the prodrug, salt or the like thereof; use of the the derivative or the prodrug, salt or the like thereof for medical purposes; and others. In the general formula (I), the rings A and B independently represent an aryl or a heteroaryl; R and R independently represent a halogen, a cyano, an alkyl, an alkylsulfonyl, -OW<1>, -SW<1>, -COW<2>, -NW<3>W<4>, -SO2NW<3>W<4>, an aryl or the like; R<C> represents H or an alkyl; Erepresents an oxygen atom or the like; U represetns a single bond or an alkylene; and X represents Y, -CO-Y, -SO2-Y, -S-(alkylene)-Y, -O-(alkylene)-Y, -SO2-(alkylene)-Y or the like [wherein Y represents Z, an amino or the like; and Z represents a cycloalkyl, a heterocycloalkyl, an aryl, a heteroaryl or the like].