This invention relates to potent selective agonists of the EP.sub.4
subtype of prostaglandin E2 receptors of formula (I), their use or a
formulation thereof in the treatment of glaucoma and other conditions
which are related to elevated intraocular pressure in the eye of the
patient. This invention further relates to the use of the compounds of
this invention for mediating the bone modeling and remodeling processes
of the osteoblasts and osteoclasts.