The AT2 receptor represents a true receptor, but signals and functions in unexpected ways compared to the respective features of the 'classical' AT1 receptor. Moreover, some of the actions of the AT2 receptor are even directly opposed to those of the AT1 receptor, especially concerning the growth- and differentiation-modulating actions of ANG II. The regulation of the AT2 receptor itself by its agonist, as well as by growth factors during ontogenesis, and its acknowledged effects on the regulation of cell growth, differentiation and apoptosis, points towards a role of a program modulator in embryonic development and regeneration.