AT4 receptors: specificity and distribution.

AT 4 receptor: Specificity and distribution. The AT 4 receptor specifically binds Angiotensin (Ang) IV and is distinct from the AT 1 and AT 2 receptors which bind Ang II and Ang III. The AT 4 receptor in bovine adrenal cortex has a K d of 0.74 ± 0.14nM and a B max of 3.82 ± 1.12 pmol/mg prot. Competition curves demonstrated the following rank order of affinity: Ang IV > Ang III > d-Arg - Ang II > Sar 1 , Ile 8 - Ang II=Ang II=Ang II (1-7) > DuP753=CGP42112A = PD 123177. AT 4 receptors were present in many tissues from several mammalian species including human and monkey. AT 4 and AT 1 /AT 2 receptors revealed a differential distribution in the rat kidney.