The present invention provides a method of treating hypertension, liver failure, loss of patency of ductus arteriosus, glaucoma or ocular hypertension in a patient, comprising administering to the patient a therapeutically effective amount of a selective EP.sub.4 receptor agonist of Formula I ##STR00001## or a prodrug thereof, a pharmaceutically acceptable salt of the selective EP.sub.4 receptor agonist or prodrug or a stereoisomer or diastereomeric mixture of the EP.sub.4 receptor agonist, prodrug or salt, wherein the variables X, Z, Q, , and R.sup.2 are as defined in the specification.