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R. G. WALES and J. C. WALLACE

Summary.

A study has been made of the effects of potassium, magnesium, calcium and phosphate ions and their possible inter-relationships on the metabolism of bull, dog, rabbit and fowl spermatozoa. Respiration and fructolysis were measured and isotopically labelled fructose used to assess the contribution of fructose oxidation to total oxygen uptake.

Overall, fowl spermatozoa had the lowest rate of metabolism. Dog spermatozoa had the greatest respiratory activity and differences in oxygen uptake between the mammalian species were due mainly to variations in the rate of fructose oxidation. Washing bull, dog and rabbit spermatozoa greatly reduced the oxidation of substrates other than fructose, but washing had little effect in the fowl.

In general, phosphate ions depressed the respiration of bull spermatozoa, but stimulated their aerobic fructolysis. Except for stimulating the respiration of unwashed dog spermatozoa, phosphate had no important influence on metabolism in the other species. Potassium stimulated some aspects of metabolism in all species, but had its greatest effect upon the respiration of dog spermatozoa. Magnesium depressed the respiration of bull and fowl spermatozoa, but calcium was without effect. There were few significant interactions between the ions tested.

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J. C. WALLACE and R. G. WALES

Summary.

The effects of potassium, magnesium, calcium and phosphate ions on the metabolism of ejaculated and epididymal ram spermatozoa have been studied. Respiration and fructolysis were measured and isotopically labelled fructose was used to assess the contribution of fructose oxidation to total oxygen uptake.

Potassium and phosphate ions significantly increased both respiration and fructolysis; magnesium and calcium had much less influence and there were few significant interactions between the ions tested.

The most significant effect of washing spermatozoa free of seminal plasma was the reduction in the oxidation of substrates other than fructose. Washing also tended to accentuate the effects of other treatments.

There were differences between ejaculated and epididymal spermatozoa in the response of oxidative metabolism to potassium but, in general, the metabolic patterns of these cells were similar.

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J. C. WALLACE and I. G. WHITE

Summary.

The occurrence of an enzyme which hydrolyses seminal glycerylphosphorylcholine (gpc) has been demonstrated in uterine rinsings of the ewe, cow, sow, rat and mouse. The products of the breakdown of gpc by rinsings of the ewe's uterus, which also contain an active phosphatase, are glycerol, inorganic phosphate and choline. Lower levels of gpc diesterase activity were also found in the cervical and oviduct fluids of the ewe. No diesterase activity could be demonstrated in the follicular fluid of the ewe, which contained appreciable concentrations of lactic acid and glucose.

Secretion of the diesterase in the ewe is influenced by the stage of the oestrous cycle independently of changes in other luminal fluid proteins or the wet weight of the uterus. Diesterase activity in uterine rinsings of the ewe is greatest at the time of ovulation.

The evidence indicates that the enzyme is a product of the uterine tissue and is not of bacterial origin. The optimal pH is 7·7 and the enzyme is not inhibited by fluoride or eserine.

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R. G. WALES and J. C. WALLACE

In a recent communication (Wales & Wallace, 1964), it was observed that the oxidation of substrates other than fructose was greatly depressed by washing the spermatozoa free of their seminal plasma. This effect could be due either to the removal of protective macromolecules in the seminal plasma or to the removal of alternative substrates. The following experiments were undertaken to investigate these possibilities. Veronal-buffered saline (pH 7·2) was the basic diluent used and the methods for preparing washed suspensions, for incubating the spermatozoa, for the assay of radioactivity and for the estimation of lactate and fructose, have been previously described (Wallace & Wales, 1964; Wales & Wallace, 1964). Sorbitol was estimated by an enzymic method (T. O'Shea and R. G. Wales, unpublished data). Acetate was estimated after steam distillation of metaphosphoric acid extracts (Annison, 1954). The
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J. C. WALLACE and A. K. LASCELLES

Summary.

An analysis of jugular blood plasma and testicular lymph collected from conscious rams has been carried out. The white cell content of the testicular lymph was 100 to 400 cells/μl and most of the cells were medium lymphocytes. In general the chemical composition of the testicular lymph was similar to that of the lymph collected from other regions of the body of sheep and other animals. The unusual composition of testicular and epididymal fluids thus was not reflected in the composition of the lymph. There was a large plasma-lymph gradient for lactate and glucose suggesting that these substances are utilized by testicular tissue. The free fatty acid level in lymph was somewhat lower than in plasma.

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R. G. WALES, J. C. WALLACE and I. G. WHITE

Summary.

Analyses were made of fluid collected from the rete testis and the caput, corpus and cauda epididymidis of the bull. Both the major electrolytes and some organic constituents in the fluids were examined. There was a decrease in sodium and chloride as the fluid passed from the testis through the epididymis and at the same time there was a general increase in organic constituents. In testicular fluid, sodium and chloride made up the bulk of the ions present. In the epididymis, however, potassium replaced approximately half of the sodium and at the same time there was a general decrease in total electrolytes. Of the organic constituents, orcinol-reactive carbohydrate, protein and acidsoluble phosphorus, especially glycerylphosphorylcholine, were present in much higher concentrations in the epididymal than in the testicular fluid. Although little reducing sugar was found, lactic acid was present in all the fluids examined.

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T. W. SCOTT, R. G. WALES, J. C. WALLACE and I. G. WHITE

Summary.

Chemical analyses have been made on fluid from the testis, caput epididymis, cauda epididymis and vas deferens of the ram. The most striking finding was a decrease in the concentration of sodium and chloride in passing from the testis through the epididymis to the vas deferens with a corresponding increase in glycerylphosphorylcholine (gpc) and total phosphorus. The concentration of protein and total orcinol-reactive carbohydrate was also much higher in the epididymis and vas deferens than in the testis. The synthesis of gpc has been demonstrated in the head and tail of the rabbit epididymis both in vivo and in vitro using 32P orthophosphate.

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F. A. MURRAY Jr, F. W. BAZER, J. W. RUNDELL, C. K. VINCENT, H. D. WALLACE and A. C. WARNICK

Restriction of embryos to the oviducal environment (tube-locked embryos) does not prevent embryonic development to the early blastocyst stage in mice (Kirby, 1962; Orsini & McLaren, 1967), rabbits (Pincus & Kirsch, 1956; Adams, 1958), rats (Alden, 1942) and sheep (Wintenberger-Torres, 1956), though further development of the tube-locked embryos has not been observed and they degenerate (Adams, 1958; Kirby, 1962; Orsini & McLaren, 1967). Kirby (1962) observed that mouse embryos recovered from the uterus continued to develop when transplanted beneath the kidney capsule; when tubelocked embryos were treated similarly only the trophoblast continued to develop. Kirby (1962) suggested that a `uterine factor' was required for the development of mouse embryos beyond the blastocyst stage. Recently, Krishnan & Daniel (1967) isolated a specific uterine