The angiotensin II receptor subtype-specific antagonists Dup 753 (AT1) and PD 123177 (AT2) were used to characterize the angiotensin II receptor subtypes present in 18 day gestation fetal Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rat brain using in vitro receptor autoradiography. The AT2 subtype was predominant in the brain of both rat strains, even in areas that display predominantly the AT1 subtype in the adult rat brain.