Parathyroid hormone regulates renal calcium homeostasis by actions on the distal nephron. PTH-induced calcium transport in mouse distal tubule (DCT) cells requires activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). ERK activation by -adrenergic receptors occurs in a biphasic manner and involves receptor internalization. An early rapid phase is -arrestin (Ar)-independent, whereas prolonged activation is Ar-dependent. We characterized PTH-stimulated ERK activation and the involvement of receptor internalization and Ar dependence. In DCT cells, PTH transiently activated ERK maximally at 5 min and then returned to baseline. Ar-dependence of PTH receptor (PTH1R)-mediated ERK stimulation was assessed using mouse embryonic fibroblasts (MEFs) from Ar1- and 2-null mice. In wild type MEFs, PTH(1-34) stimulated ERK activation peaked after 5 min, was 50% maximal after 15 min and then recovered to 80% of maximum stimulation by 30 min. In MEFs null for Ar1 and 2, PTH-stimulated ERK activation peaked by 5 min and returned to baseline. The effect was identical in Ar2-null MEFs. In Ar1-null MEFs ERK exhibited delayed activation and remained elevated. PTH-stimulated ERK activation and receptor endocytosis were not inhibited by the clathrin-binding domain of Ar1 (Ar[319-418]). Co-expression of the sodium proton exchanger regulatory factor 1 (NHERF1) with Ar[319-418] blocked PTH1R internalization. We conclude that PTH-stimulated ERK activation in DCT cells proceeds with a rapid, but transient phase that may involve Ar1. Furthermore, the Ar-dependent late phase of ERK activation by PTH requires the participation of Ar2 and PTH1R internalization.