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A. POULOS and I. G. WHITE

Summary.

The phospholipid composition of human spermatozoa and seminal plasma was examined by quantitative two-dimensional thinlayer chromatography, followed by phosphorus analysis. Sperm phospholipid comprised 28·8% phosphatidyl choline, 21·6% phosphatidyl ethanolamine, 21·4% sphingomyelin, 9·4% ethanolamine plasmalogen, 4·7% phosphatidyl serine, 2·7% choline plasmalogen, 1·9% phosphatidyl inositol and 1·6% cardiolipin.

Seminal plasma phospholipids comprised 44·0% sphingomyelin, 12·3% ethanolamine plasmalogen, 11·2% phosphatidyl serine, 8·5% phosphatidyl ethanolamine, 7·8% phosphatidyl choline, 0·8% choline plasmalogen, 0·8% cardiolipin and 1·7% phosphatidyl inositol.

Prolonged aerobic incubation of human spermatozoa in the presence or absence of glucose produced no significant alteration either in the amount of phospholipid phosphorus extracted or in the phospholipid composition of this extracted material.

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I. G. WHITE and R. G. WALES

Summary.

A comparison has been made of the physiological and chemical properties of ejaculated and epididymal semen collected from rams with a surgical fistula into one vas deferens.

The most striking difference between the spermatozoa was the resistance of epididymal cells to cold shock, which was correlated with the attachment of kinoplasmic droplets.

Other intrinsic differences between the spermatozoa were small and there was little evidence of a difference in metabolic pattern.

The two types of seminal plasma differed considerably in chemical composition, although the pH was about the same and glycerylphosphorylcholine was present in high concentration in both.

Evidence was obtained that the fructose in ejaculated ram semen enables the motility of the spermatozoa to be better maintained under anaerobic conditions than is the case with epididymal spermatozoa.

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R. G. WALES and I. G. WHITE

Summary.

The motility of dog spermatozoa is depressed by high dilution. Dog spermatozoa survived best in a chloride diluent, buffered with phosphate. Citrate, tartrate and peptone diluents were less favourable. Adding 2 to 25% prostatic fluid to diluents partially prevented the effects of dilution on dog spermatozoa, but motility was depressed by neat prostatic fluid. There was little evidence for loss of protective substances from dog spermatozoa when left overnight, or after repeated freezing and thawing. Bovine globulin, casein, egg albumin and alanine were even more effective than prostatic fluid in preventing the dilution phenomenon, and motility in their presence was as good as in concentrated suspensions. Egg albumin, casein, acacia, serine and alanine improved the motility of washed dog spermatozoa.

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R. G. WALES and I. G. WHITE

Summary.

Penicillin, streptomycin and the sulphonamides were well tolerated by dog spermatozoa. Penicillin did, however, become more toxic on storage at 37° C in neutral or alkaline solutions.

Chloromycetin and the tetracycline derivatives were much more spermicidal and greatly reduced oxygen uptake, lactic acid production and fructose utilization.

Sulphamezathine and tetracyn were superior to other antibacterials in maintaining the viability of dog spermatozoa stored at 5° C.

The toxicity of high concentrations (2000 μg/ml) of biotin was reduced by aureomycin.

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R. G. WALES and I. G. WHITE

Summary.

Data are presented on the chemical composition of the three fractions of dog semen. Sodium is the main cation present in all fractions; potassium, magnesium and calcium occur in much lower concentration. Chloride is the main anion. All fractions are characterized by low concentrations of total reducing sugar, fructose, lactic acid and citric acid. Orcinol reactive carbohydrate is present in significant amounts and much is acid insoluble and probably bound to protein.

The sperm-bearing fraction is characterized by a high concentration of total phosphorus and the acid insoluble fraction is mainly confined to the spermatozoa. The high concentration of acid soluble phosphorus in this fraction is partly due to the appreciable amounts of glyceryl-phosphorylcholine present.

Analyses of seminal carbohydrate and protein indicate inherent differences between dogs in the composition of semen.

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J. C. Rodger and I. G. White

Department of Veterinary Physiology, University of Sydney, N.S.W. 2006, Australia

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R. A. P. HARRISON and I. G. WHITE

Summary.

A method has been developed for the simultaneous isolation of spermatozoa and cytoplasmic droplets from bull, boar and ram semen. The glycolytic enzymes, hexokinase (HK), glucose phosphate isomerase (GPI) and lactate dehydrogenase (LDH) were demonstrated in both types of particle: on a per particle basis compared with spermatozoa, droplets contained similar quantities of GPI, less HK and only one-tenth the amount of LDH. The HK was partly bound while the GPI was entirely soluble in both. The LDH was partly bound in spermatozoa but soluble in droplets.

Suspensions of spermatozoa and cytoplasmic droplets were subjected to sudden cooling, freezing or hypo-osmotic shock, and leakage of GPI, HK and LDH into the extracellular medium was measured. Both spermatozoa and droplets released glycolytic enzymes during the treatments, but the droplets were more fragile than the spermatozoa. The proportion of loss varied between enzymes, as well as between droplet and spermatozoon; considerable GPI and little HK was released from both, whereas much LDH was lost from droplets but hardly any from spermatozoa.

The activities of these three glycolytic enzymes were also measured in seminal plasma from bull, boar and ram. The ratios of the activities found were compared with those in droplets or spermatozoa from the same species. It is suggested that much of the glycolytic enzyme activity in seminal plasma arises from disintegrated cytoplasmic droplets rather than from spermatozoa.

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E. S. E. HAFEZ and I. G. WHITE

Summary.

The activity of alkaline phosphatase, acid phosphatase, glutamic-oxalacetic transaminase (got), lactic dehydrogenase (ldh), amylase, succinic dehydrogenase (sdh) and glucose-6-phosphate dehydrogenase (gph) has been determined in the intercaruncular and caruncular areas of the endometrium during the follicular and luteal phases of the oestrous cycle and from 13 to 35 days of pregnancy in the ewe.

The activities of the enzymes in the two areas of the endometrium were similar except that alkaline phosphatase activity was higher, and sdh lower, in the intercaruncular area.

During the luteal phase of the oestrous cycle and during early pregnancy, alkaline and acid phosphatase activities increased in the intercaruncular and caruncular areas. Amylase and got values were also elevated in the caruncular area during early pregnancy. The level of ldh in the intercaruncular area of the endometrium was less during the luteal phase than during the follicular phase of the oestrous cycle.

Enzyme activity was variable in the chorion, embryo and blastocoelic fluid. The only statistically significant change was a sharp rise in the acid phosphatase concentration of the blastocoelic fluid at 31 to 35 days of pregnancy.

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J. K. VOGLMAYR and I. G. WHITE

Summary.

The synthesis of inositol from glucose by ram testicular and ejaculated spermatozoa has been examined. During incubation for 2 hr under air, the intracellular accumulation of substrate carbon accounted for 10·2% and 2·3% of the glucose utilized by testicular and ejaculated spermatozoa respectively. Some 65 to 75% of the substrate carbon accumulating in testicular spermatozoa was inositol, whereas in ejaculated spermatozoa only trace amounts of the cyclitol were detectable. When incubated without exogenous substrate, testicular spermatozoa utilized intracellular inositol and accumulated labelled metabolites. The addition of extracellular inositol failed to stimulate the respiration of testicular or ejaculated spermatozoa above endogenous levels although small amounts of the cyclitol were oxidized. Rete testis fluid increased the oxygen uptake of testicular and ejaculated spermatozoa and increased the uptake of substrate carbon from inositol present in the fluid. It is suggested that the cytoplasmic droplet may be the site of inositol synthesis in the testicular spermatozoa.

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R. N. MURDOCH and I. G. WHITE

Summary.

There was usually an increase in the manometrically determined oxygen uptake of rabbit spermatozoa which has previously been subjected to an incubation in the uterus of the doe, and also an increase in aerobic glycolytic activity as estimated by glucose utilization and lactate accumulation. Freshly ejaculated rabbit spermatozoa produced aerobically about as much labelled carbon dioxide from [6-14C]glucose as from [1-14C]glucose, whereas spermatozoa incubated in utero oxidized [1-14C]glucose at a rate distinctly above that shown by fresh spermatozoa. The time required for the development of these metabolic changes was similar to that required for the capacitation of rabbit spermatozoa.

Rabbit spermatozoa maintained in vitro for 2 hr or more at 37° C suffered a marked decline in metabolism. The yield of 14CO2 from [1-14C]glucose, however, declined less than that from [6-14C]glucose.