PD123319 is a non-peptide inhibitor of angiotensin II receptor with IC50 value of 34nM . Angiotensin II play roles in a variety of physiological functions. Among these, the most prominent is vascular contraction. Unlike previous drugs act as inhibitors of the formation of Ang II or ACE, PD123319 is an antagonist of angiotensin II receptor. PD123319 shows inhibition potency in both rat adrenal and brain binding assay with IC50 values of 34nM and 210nM, respectively. It is found to prevent Ang II from binding the bovine zona glomerulosa microsomal preparation with IC50 value of 6.9nM in the binding assay using microsome. In addition, it is reported that administration of PD123319 can suppress the generation of cyclic guanosine monophosphate and increase the production of prostaglandin E2. Besides that, administration of PD-123319 does not infiuence the effect of Ang II on protein tyrosine phosphorylation or thymidine incorporation .