It has been reported previously that platelet-derived growth factor (PDGF) may play an important role in the regulation of lens growth and differentiation. To evaluate PDGF-induced effects at the cellular level, we investigated the response of cultured bovine lens epithelial cells (BLEC) to PDGF-AB, -AA, and -BB isoforms at the cellular level. Stimulation of BLEC with PDGF isoforms showed no increase in cell proliferation under the culture conditions of this study. In contrast, measurement of cytosolic free calcium concentration ([Ca2+]i), which has been shown to be an important second messenger for controlling multiple cellular processes in the lens, revealed a dose-dependent rise in [Ca2+]i upon stimulation with PDGF-AB and -BB isoforms. PDGF-AA used in similar concentrations was not effective. Our data suggest that PDGF-AB and -BB may play a role in the regulation of cellular functions in BLEC via modulation of intracellular calcium homeostasis.