19(R)-Hydroxylated prostaglandins (PGs) occur in μg/ml concentrations in the semen of certain mammalian species, especially primates. In the case of humans, the compounds are primarily of the PGE series, and the hydroxyl stereochemistry is 15(S),19(R).
1 19(R)-Hydroxylated PGs are also found in the seminal plasma of marsupials, where F-type compounds of the 1 and 2-series predominate.
2 The 15(R)-hydroxy epimer of these 19-hydroxylated PGs is the inverse or “unnatural” isomer at C-15. The biological role of 19(R)-hydroxylated PGs is not well established. In the F-series, 19(R)-hydroxylation is associated with a significant loss of receptor-mediated biological activity in some assays.
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1. Cooper, I., and Kelly, R.W. The measurement of E and 19-hydroxy E prostaglandins in human seminal plasma Prostaglandins 10(3),507-514(1975).
2. Marley, P.B., Rodger, J.C., White, I.G., et al. 19-Hydroxylated prostaglandins in the semen of the marsupial Trichosurus vulpecula (brush-tailed possum) Comp. Biochem. Physiol. B Biochem. Mol. Biol. 70(3),619-621(1981).
3. Woodward, D.F., Protzman, C.E., Krauss, A.H.P., et al. Identification of 19(R)-OH prostaglandin E2 as a selective prostanoid EP2-receptor agonist Prostaglandins 46(4),371-383(1993).
