(R)-Butaprost

Butaprost is a structural analog of prostaglandin E₂ (PGE₂) with good selectivity for the EP₂ receptor subtype. Butaprost has frequently been used to pharmacologically define the EP receptor expression profile of various human and animal tissues and cells.^1,2 Serious confusion as to the structure of butaprost was generated by Gardiner in 1986, when he reported that the epimer of butaprost showing this selective activity was the C-16 (R)-epimer (See Note).³ Butaprost binds with about 1/10 the affinity of PGE₂ to the recombinant murine EP₂ receptor, and does not bind appreciably to any of the other murine EP receptors or DP, FP, IP, or TP receptors.⁴ The pharmacology of (R)-butaprost has not been carefully studied, but it is generally considered to be the less active epimer.⁵ NOTE: In the Gardiner paper in the 1986 British Journal of Pharmacology, butaprost appears on page 46 where it is given the name TR 4979. The structure as drawn is incorrect, in that the author was using and referring to the more active C-16 epimer, which is actually 16(S). The structure on page 46 shows the structure as 16(R). It was not until the late 1990’s that careful studies both in the US and Japan correctly identified the actual configuration of C-16 in the compound called butaprost is 16(S).³

WARNING This product is not for human or veterinary use.

1. Lawrence, R.A., and Jones, R.L. Investigation of the prostaglandin E (EP-) receptor subtype mediating relaxation of the rabbit jugular vein. Br. J. Pharmacol. 105(4), 817-824 (1992).

2. Talpain, E., Armstrong, R.A., Coleman, R.A., et al. Characterization of the PGE receptor subtype mediating inhibition of superoxide production in human neutrophils. Br. J. Pharmacol. 114(7), 1459-1465 (1995).

3. Gardiner, P.J. Characterization of prostanoid relaxant/inhibitory receptors (XyX) using a highly selective agonist, TR4979. Br. J. Pharmacol. 87(1), 45-56 (1986).

4. Kiriyama, M., Ushikubi, F., Kobayashi, T., et al. Ligand binding specificities of the eight types and subtypes of the mouse prostanoid receptors expressed in Chinese hamster ovary cells. Br. J. Pharmacol. 122(2), 217-224 (1997).

5. Regan, J.W., Bailey, T.J., Pepperl, D.J., et al. Cloning of a novel human prostaglandin receptor with characteristics of the pharmacologically defined EP₂ subtype. Mol. Pharmacol. 46(2), 213-220 (1994).