Prostaglandin E2 antagonizes the renal effects of parathyroid hormone but not those mediated by a cyclic AMP analog.

An infusion of PGE2 resulted in the development of refractoriness to the phosphaturic effects of PTH in the chronically TPTX dog. The antagonism of PGE2 to the actions of PTH was not observed when the phosphaturia was stimulated by the cAMP analog, 8-bromo cAMP. We propose that the development of antagonism to the actions of PTH by PGE2 is localized to cellular events proximal to the generation of tubular cAMP. This antagonism by PGE2 could be an effective regulatory mechanism of hormonal action at the local level.