The present invention provides a compound which is useful as a PGI.sub.2 receptor agonist, and a pharmaceutical composition.The present invention is directed to a pharmaceutical composition comprising a compound represented by the following formula [1]: ##STR00001## (R.sup.1 and R.sup.2 are the same or different and each represents optionally substituted aryl, Y represents N or CH, Z represents N or CH, A represents NH, NR.sup.5, O, S, or ethylene, R.sup.5 represents alkyl, D represents alkylene or alkenylene, E represents phenylene or single bond, G represents O, S, or CH.sub.2, R.sup.3 and R.sup.4 are the same or different and each represents hydrogen or alkyl, Q represents carboxy, alkoxycarbonyl, tetrazolyl, carbamoyl, or N-(alkylsulfonyl)carbamoyl), or a pharmaceutically acceptable salt thereof as an active ingredient.