In vitro activity: PD 123319 ditrifluoroacetate is a novel, potent, and selective nonpeptide AT2 (angiotensin II) receptor antagonist with IC50 of 34 nM. It displaces 125I-labeled angiotensin II from a specific subset of angiotensin II binding sites in rat adrenal preparations. PD 123319 has been used to selectively examine the specific roles for AT1R and AT2R in hypertensive and other vascular research-related models. PD-123319 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.

Kinase Assay: PD 123319 is shown to discriminate between two subclasses of AII receptors in many different tissues. 125I-AII specifically labeled two classes of binding sites for AII in a membrane preparation of bovine adrenal glomerulosa cells. The first class (DuP-753 sensitive) represents approximately 85% of the total binding sites for AII and possesses a high affinity (IC50 of 92.9 nM) for DuP-753. PD-123319 does not have any effect on 125I-AII binding to this site. The second class of binding sites is more sensitive to PD-123319, with an IC50 of 6.9 nM, and has a much lower affinity for DuP-753 (IC50 around 10 μM).

Cell Assay: PD123319 suppressed osteogenic differentiation of human mesenchymal stem cells through inhibition of extracellular signal-regulated kinase signaling.