TIP39, a neuropeptide and an agonist for the parathyroid hormone receptor type 2 (PTH2R), effectively increases cAMP levels in COS-7 cells featuring recombinant PTH2R from humans or rats (EC50s = 0.5 and 0.8 nM, respectively), as well as in F-11 cells that naturally express PTH2R (EC50 = 1.15 nM). Furthermore, TIP39 at 1 nM halts the cell cycle at the G0/G1 phase and reduces Sox9 expression, a crucial regulator of cartilage differentiation, in CFK2 rat chondrocytes. Additionally, administering 100 pmol/animal of TIP39 reduces the immobility period in the forced swim test in mice, indicating a potential antidepressant effect.