Seminal fluid, source

Lasers (qv) and other high intensity or alternative light sources are usefiil in crime laboratories to visualize latent fingerprints, seminal fluid stains, obhterated writings, and erasures, and to aid in specialized photographic work. Infrared and ultraviolet light sources are also used to view items of evidence. 

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. 

The prostate is both a blessing and a curse. This small walnut-shaped organ surrounds the urethra (the tube through which urine passes) and is situated at the base of the bladder. It is the source of seminal fluid and is thus intimately involved in maintenance of sexual performance and libido. But to many men over the age of 40 (and to just about all over the age of 70), it is a source of annoyance and discomfort. With advancing age, the prostate grows and begins to constrict the urethra, reducing urine flow - a condition known as prostatic hyperplasia. 

This pathway is present in seminal vesicles, which synthesize fructose for the seminal fluid. Spermatozoa use fructose as a major fuel source while in the seminal fluid and then switch to glucose once in the female reproductive tract. Utilization of fructose is thought to prevent acrosomal breakdown of the plasma membrane (and consequent activation) while the spermatozoa are still in the seminal fluid. 

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. 

The original description of zinc deficiency in humans included lack of pubertal development. Spermatogenesis is a zinc-dependent process. Seminal fluid is particularly rich in zinc, and the sperm appear to accumulate zinc from this source prior to ejaculation. Zinc is also crucial for normal fetal development, and deficiency leads to abnormalities in humans and animals. Maternal zinc deficiency has been linked with pregnancy-associated morbidity, including pre-term delivery. 

The prostate gland and the seminal vesicles secrete the bulk of the fluid. The sources, contents and functions of the secretions from the accessory glands are given in Table 19.1. 

As long ago as 1935, Kutscher and Wolbergs (K12) observed that semen and the prostate are among the richest sources of acid phosphatase in the human body. In a more recent survey (Bll) the acid phosphatase activities of seminal plasma in various species, determined as milligrams of nitrophenol liberated by 100 ml seminal plasma from 0.006 M p-nitrophenyl phosphate, in 60 minutes at 37°C and pH 4.9 were human, 274,000 cock, 15,000 turkey, 4000 bull, 570 rabbit 85. Human seminal plasma is made up by the secretory fluids produced in the epididymides, vasa deferentia, ampullae, seminal vesicles, the prostate and the bulbourethral (Cowper s) and urethral (Littre s) glands (M4). The semen contains many particulate bodies. Best known, of course, are the spermatozoa, which are formed in the seminiferous... 

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