AGT and Hypertension: The earlier studies were conducted in cultured rat and human embryonic kidney 293 cells; Parker et al. demonstrated that inhibition of sphingosine kinase 1 (SK1) attenuated the second phase of transmembrane Ca2+ ion influx in Ang II-mediated hypertension, suggesting a role for sphingosine kinase 1 in Ang II-dependent activation of SOC [90].