Seminal fluid, prostaglandin source

As early as 1930, it was recognized that seminal fluid contains materials that promote contraction of uterine muscles. The active compounds, the prostaglandins, were isolated and crystallized in 1960 and were identified shortly thereafter.257 258 As many as 14 closely related compounds are found in human seminal fluid, one of the richest known sources. Prostaglandins are present in seminal fluid at a total concentration of 1 mM, but their action on smooth muscles has been observed at a concentration as low as 10 9 M. 

Prostaglandins occur in a wide variety of animal tissues and there are a number of instances where they are released on tissue stimulation or activation. Human seminal fluid is the richest source where thirteen different members of the series have been identified (Ej, E2, E3, Fi F2 Ai, A2, Bi, B2 and 19-OH Ai, A2, Bj and B2) with a total concentration of about 300 ng/ml [22, 23]. Considerable species variation is exhibited both in the number and concentration thus only five of these thirteen [24] are found in ram semen and that of some other species contains none at all [5]. The ram vesicular gland is an important source of prostaglandins and the enzyme system from this organ is used for laboratory synthesis starting from added fatty acid precursors [25]. 

More than 50 years ago a compound was discovered in the seminal fluid and in the prostate which caused contraction of smooth muscle cells [12]. Although the chemical structure of this factor remained unclear for many years, it was named prostaglandin because of its organ source. Since then the chemical structures of a variety of prostanoids have been identified, and we also know that the prostate is not the only, and not even the major, source of prostaglandin (PG) formation. Moreover, most enzymes involved in prostaglandin biosynthesis have been well characterized. 

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