Cecilia Lutwak-Mann

Biochemistry of Seminal Plasma and Male Accessory Fluids; Application to Andrological Problems

Many years were to pass after this pronouncement upon the uniqueness of the seminal plasma by Louis Nicolas Vauquelin (author of ‘Experiences sur le sperme humain’, the earliest treatise on the chemistry of semen), before its origin and site of formation were properly established and the complex chemical nature of this fluid began to be inquired into.

Secretory Function of the Prostate, Seminal Vesicle, Cowper’s Gland and Other Accessory Organs of Reproduction

The complicated make-up of the seminal plasma, and the role which the male accessory secretions play in the elaboration of this body fluid did not escape the notice of Littre and other anatomists of his day, but over two centuries passed before the properties of the individual secretions were recognized and their physicochemical characteristics elucidated. It took some time again before primitive examination of accessory glands by palpation or at laparotomy as the sole criterion of their functional condition was replaced by quantifiable biochemical methods. The rationale for the adoption of the modern approach rests upon the fact that these glands secrete a number of characteristic substances that at ejaculation enter the semen, in which they can be determined accurately in very small amounts of material. The chemical methods have stood the test of time well and have been discussed at length (Mann 1974b, 1975a; Mann and Lutwak-Mann 1976). Only relatively recently, as a result of chemical investigations, has the extent of the remarkable species differences in the secretory activity of the accessory glands received due attention. At the same time it became clear that species variations apart, there are considerable individual fluctuations in the secretory output, arising from differences in the size of accessory organs and conditioned by hormonal influences in the prostate and seminal vesicles in particular.

The Dependence of Gonadal Function upon Vitamins and Other Nutritional Factors

Publisher Summary For a considerable number of years the relationship existing between the function of the gonads and nutrition in the widest sense has been receiving a great deal of attention, and there is, therefore, no lack of admirable treatises and surveys, not a few of them in the preceding volumes of “Vitamins and Hormones,” pertaining to various aspects of this problem. This profusion of excellent, well-documented, and detailed reviews has a somewhat intimidating influence, creating one doubt that if anything new and of real value could be added to what has so ably been stated before. This particular biological problem is one with regard to which there are absolutely no signs of flagging interest, therefore, the very example of sustained scientific endeavor inspires and spurs to master the imposing wealth of data, observations, and discoveries relating to the effect which dietary factors exert upon the gonads and to marshal the facts in a more or less well-ordered sequence, not necessarily always according to historical precedence, into a coherent whole to serve as another stepping stone for those who wish to follow.

Male Reproductive Function and the Composition of Semen: General Considerations

The modern era of the physiology of reproduction in the male is commonly, and rightly so, accepted as having been ushered in by Leeuwenhoek’s sensational letter to the Royal Society, dated November 1677, reporting the first-ever demonstration in semen of motile spermatozoa. From another of his famous communications, cited above and submitted 8 years later, it is evident that Leeuwenhoek intuitively associated the existence of spermatozoa with male fertilizing ability, by recognizing that even though a man may be keenly interested in the opposite sex, this alone is not enough to guarantee the birth of offspring. He anticipated, moreover, yet another basic concept of male reproductive biology, by proclaiming that for the act of procreation to be fulfilled, the spermatozoa, as well as being motile, must also be sufficiently energetic to survive in the female tract for a certain period, presumably to attain their full potential. The precise duration of that critical timespan he was, of course, unable to back up with experimental evidence.

Biochemical Aspects of Aging in Spermatozoa in Relation to Motility and Fertilizing Ability

Sperm aging is defined as a gradual and irreversible decay in structural mechanochemical and fertilizing properties of mature spermatozoa. Research using artificial means such as cold shock freezing and thawing dilution and washing treatment with spermiostatic and spermicidal substances and by prolonged storage has provided insight into biochemical aspects of sperm senescence under conditions in vitro. Biochemical investigations indicate that degenerative changes in spermatozoa are initiated in sperm membranes and the acrosome. An early sign of degeneration is the swelling of the acrosomal and plasma membranes causing an increase in cellular permeability followed by accelerated penetration of extracellular substances and loss through leakage from spermatozoa of essential intracellular elements. Enzymes released from degenerating spermatozoa are either of lysosomal nature stemming from various components of the acrosomal complex or are glycolytic enzymes and cytochrome c and are derived from other organelles including mitochondria. Another factor in sperm aging is nuclear instability. Evidence indicates that the minute amount of RNA contained in spermatozoa is synthesized on the mitochondrial and not the nuclear DNA template. Fertilizing ability of spermatozoa as seen in investigations with mammalian semen stored in vitro or surviving the female reproductive tract can be lost before motility and metabolic activity has stopped. The definition of sperm aging ultimately depends on the choice of criteria applied in sperm viability evaluation.

Epididymis and Epididymal Semen

On emerging from the efferent ducts the spermatozoa enter the epididymis, an organ consisting of a highly convoluted duct system reputed to cover a total length of about 20 metres in man, 40 in the bull and 60 in the boar; it is strictly dependent upon testicular androgen for the maintenance of its structure as well as secretory, resorptive, biosynthetic and metabolic activity. The major component parts of the epididymis are customarily referred to as head (caput), body (corpus) and tail (cauda), but in fact, each of these three regions possesses subsegments which exhibit their own distinct cell types and functional peculiarities. The structure and function of the epididymis, the histochemical differences between the various regions and subsegments, and the influence of the different zones upon the passage and function of epididymal spermatozoa have all been extensively discussed (Alsum and Hunter 1978; Bedford 1966, 1974, 1975, 1978a, 1979; Brooks 1979b; Fouquet and Guha 1969; Glover and Nicander 1971; Hamilton 1972, 1975; Martan 1969; Moniem and Glover 1972a; Nicander and Glover 1973; Nicander and Hellstrom 1967; OrgebinCrist 1969; Orgebin-Crist et al. 1975; Voglmayr 1975b; White 1973). The newer techniques evolved for the study of structure-function relationships in the epididymis (and the prostate) include certain stereological methods of quantitating three-dimensional structures from measurements of two-dimensional cross sections (Bartsch et al. 1978).

Metabolic Activity in Tissue Transplants. Hormone-Induced Formation of Fructose and Citric Acid in Transplants from Accessory Glands of Reproduction

A combined chemical and cytological study of the behaviour of transplants from certain accessory glands of reproduction in the rat was carried out. It was found that subcutaneous transplants of coagulating gland and seminal vesicle were capable of producing considerable amounts of fructose and citric acid in total anatomical separation from the male reproductive system. In transplants containing coagulating gland and seminal vesicle tissue both fructose and citric acid were formed. In those from coagulating gland alone only fructose was produced, but citric acid was absent. In this respect the metabolic behaviour of the grafts was identical with that of the intact organs. Following castration, coagulating gland transplants lost their ability to form fructose. This was fully restored by treatment with testosterone propionate. Upon cessation of the hormone treatment the process of fructose formation in the transplants was again brought to a standstill. Grafts of coagulating gland could be successfully grown in female rats and brought to a state of fructose secretion by subjecting the female hosts to injections of male sex hormone. The post-castrate retrogressive changes as well as the hormone-induced recovery symptoms were studied in the transplants parallel with similar changes in the intact glands in situ. The chemical findings were corroborated by the histological examination.

Secretion of fructose and citric acid in transplants of rat seminal vesicle and coagulating gland.

Summary Subcutaneous transplants of coagulating gland and seminal vesicle in rats, were capable of producing fructose and citric acid when grown a) in normal males, b) castrated testosterone-treated males, and c) testosterone-treated non-spayed or spayed females.

Activity of the succinic dehydrogenase.

IT has long been held that the succinic dehydrogenase requires no co-enzyme or intermediary hydrogen carrier to link its activity with that of the cytochrome system.

Collection, Examination, Quality Rating and Storage of Ejaculated Semen

Semen collection is something between a craft and an art, more or less difficult depending upon the animal species that one is working with. Individual experimenters differ greatly in the degree of mastery of techniques that have been elaborated for this purpose over the years; some are demonstrably better at it than others.