Anterior pituitary cells release ATP and express several subtypes of purinergic P2 receptors, but their biophysical properties and roles in spontaneous and receptor-controlled electrical activity have not been characterized. Here we focused on extracellular ATP actions in gonadotrophs from embryonic, neonatal, and adult rats. In cells from all three age groups, the Ca²⁺-mobilizing agonist GnRH induced oscillatory, hyperpolarizing, non-desensitizing, and slow deactivating currents. In contrast, ATP induced non-oscillatory, depolarizing, slowly desensitizing, and rapidly deactivating current, indicating that these cells express cation-conducting P2X channels but not Ca²⁺-mobilizing P2Y receptors. The amplitudes of P2X current response and the rates of receptor desensitization were dependent on ATP concentration. The biophysical and pharmacological properties of P2X currents were consistent with the expression of P2X₂ subtype of channels in these cells. ATP-induced rapid depolarization of gonadotrophs lead to initiation of firing in quiescent cells, an increase in the frequency of action potentials in spontaneously active cells, and a transient stimulation of LH release. ATP also influenced GnRH-induced current and membrane potential oscillations and LH release in an extracellular Ca²⁺-dependent manner. These InsP₃-dependent oscillations were facilitated, slowed, or stopped, depending of ATP concentration, the time of its application, and the level of Ca²⁺ content in intracellular stores. These results indicate that in gonadotrophs P2X receptors could operate as pacemaking channels and modulators of GnRH-controlled electrical activity and secretion.