19-HydroxyIated E prostaglandins as the major prostaglandins of human semen

Abstract

ALMOST 30 years after the initial discovery of the prostaglandins, Bergstrom et al., succeeded in isolating and identifying prostaglandins (PGs) E₁, E₂, F_1α and F_2α from sources including human semen¹. It was subsequently claimed² that the 19-hydroxy derivatives of prostaglandins A and B were also present. These compounds were later found at an average concentration of 40 µg ml⁻¹ (ref. 3), In a detailed study of semen PGs we have used a new approach for the measurement of the E prostaglandins, which involves protecting the unstable β-ketol system by oximation in the unextracted semen, thus ensuring minimal degradation to the A or B series. Using this technique we found that the levels of 19-hydroxy derivatives of PGA and PGB are relatively low whereas two new PGs, later identified as 11_α,15,19-trihydroxy-9-keto prost-13-enoic acid (19-hydroxy PGE₁) and 11_α,15,19-trihydroxy-9-keto prosta-5,13-dienoic acid (19-hydroxy PGE₂) were present at an average total concentration of 100 µg ml⁻¹. These compounds can be isolated together as the methyl ester/methyl oxime derivatives by thin layer chromatography and the individual components can be separated by gas chromatography as the methyl ester/methyl oxime/tert-butyl dimethyl silyl ethers⁴.