Secretion Rates and Chemical Composition of Oviduct and Uterine Fluids in Sows

The chemical composition of uterine fluid collected from ewes cannulated by three different procedures was studied.Sodium and chloride were the major inorganic ions present. Smaller amounts of potassium, magnesium, calcium, ammonium, bicarbonate, and phosphate ions were also found. Orcinol-reactive carbohydrate was present in high concentration but only 1--4 % could be accounted for as the reducing sugar, glucose. Approximately 5 mM lactate was present in the uterine secretions.Protein concentration varied from 1 to 3 g/loo ml and some differences existed between uterine fluid and blood serum both in electrophoretic mobility and relative concentration of the various protein components. Uterine fluid also differed in amino acid composition from blood serum and the results suggest that uterine fluid is, at least in part, a true secretion and not merely a blood transudate.Differences in chemical composition between stages of the oestrous cycle were small and only minor differences were found between fluid collected from the uterine horn and that collected from the body of the uterus. By contrast the composition of fluid collected from ewes with a cannula inserted through the cervical canal differed considerably from that of fluid collected by the other two methods of cannulation and the former method may give a less reliable estimate of the true uterine environment.

Section: Discussionsupporting

confidence: 89%

The Uterus of the Ewe II. Chemical Analysis of Uterine Fluid Collected by Cannulation

Rg¹

1973

“…Amino acids are present in uterine secretions in considerable amounts (Gwatkin 1969;Iritani et al 1971;laszczak and Hafez 1972;Wales 1973) and have been implicated in the biology of development. Their uptake and incorporation into the mouse embryo has been demonstrated both in vitro (Brinster 1971;Smith and Smith 1971;Epstein and Smith 1973;Epstein 1975) and in vivo (Greenwald and Everett 1959;Weitlauf and Greenwald 1965) and some have been shown to be important for the outgrowth of the embryo in vitro (Gwatkin 1966).…”

Section: Discussionmentioning

confidence: 99%

“…They appear in relatively high concentrations in uterine secretions (Gwatkin 1969;Iritani et al 1971;J aszczak and Hafez 1972;Wales 1973) and could act as an important alternative energy source for the developing embryo. If this is so, their presence in the environment during development could influence the metabolism of simple energy substrates such as glucose and affect the resultant accumulation of glycogen during development in vivo.…”

Section: Introdnctionmentioning

confidence: 99%

Influence of Environmental Factors on the Metabolism of Glucose by Preimplantation Mouse Embryos in vitro

Edirisinghe¹,

Wales²

1985

The metabolism of glucose by late pre implantation mouse embryos was studied in a variety of media whose composition had been changed to reflect the environmental conditions in the uterus more closely than do standard culture media. The effects of combinations of energy substrates, the presence or absence of amino acids and the level of potassium in the medium were investigated.The use of energy substrates for in vitro culture at levels present in the uterine environment resulted in rates of synthesis and degradation of glycogen pools similar to those obtained using standard in vitro culture conditions but elevated incorporation into non-glycogen macromolecules. Amino acids influenced the metabolism of glucose by limiting the entry of glucose carbon into the non-glycogen macromolecular pool and directing more glucose into the synthesis of acid-soluble glycogen.Increasing the K + concentration to 60 mM in the culture medium caused a small but significant increase in the number of eight-cell embryos degenerating during culture for 24 h but the metabolism of glucose was unaffected over this time. At the time of morula transformation to the blastocyst this level of potassium ions suppressed glycogen synthesis by 50% over 5 h but did not affect its turnover during chase culture.It is concluded that factors other than those studied here contribute to the maintenance of the low glycogen levels found in uterine embryos. IntrodnctionEarlier work (Ozias and Stern 1973;Ozias and Weitlauf 1971;Snyder et al. 1971;Edirisinghe et al. 1984aEdirisinghe et al. , 1984b indicates that the uterine environment influences the metabolism of late preimplantation mouse embryos and in particular the utilization of glycogen stores. This environment is more complex than, and differs in the range and concentration of components from, the standard chemically defined media normally used for in vitro culture (Hamner 1971;Wales 1973;Beier 1974; Edirisinghe and Wales 1985). Changes in the environment may well be important in modifying the metabolism of glucose by embryos and be responsible for the differences in the turnover of glycogen in vivo as compared to its utilization in vitro.The possible control of glycogen metabolism by the level of exogenous energy substrate has been studied using different concentrations of the major energy substrates, glucose, lactate and pyruvate (Pike and Wales 1982). It is clear from this study that embryos, especially at the late preimplantation stages, have the ability to synthesize large amounts of glycogen and that the presence of the alternative energy substrates, lactate and pyruvate during culture influences the synthesis of glycogen, particularly when the medium contains a low concentration of glucose. Recently, the levels of lactate, pyruvate and glucose in the uterine fluid of mice have been measured and found 0004-9417/85/040411 $02.00

“…The importance of such metabolic alterations to spermatozoa in the female tract is not known with any certainty, but adequate amounts of potassium and bicarbonate together with utilizable substrates such as pyruvate and lactate are present in the female genital tract secretions to cause a stimulation of spermatozoal metabolism in utero (Vishwakarma 1962;Restall and Wales 1968;Spilman et al 1970;Iritani et al 1971). Rogers and Yanagimachi (1975) and Rogers et al (1977) have suggested that the processes of capacitation and the acrosome reaction of spermatozoa are metabolically controlled and that pyruvate and lactate play important roles in this respect.…”

Section: Discussionmentioning

confidence: 99%

Effects of Bicarbonate on the Respiration and Glycolytic Activity of Boar Spermatozoa

Murdoch¹,

Davis²

1978

The metabolism of washed boar spermatozoa was studied in the presence and absence of low levels of bicarbonate (6 mM) and carbon dioxide (2 %). Bicarbonate stimulated the oxygen consumption of the spermatozoa but had no apparent effect on glycolysis. The stimulatory effect of bicarbonate on respiration depended on the presence of a utilizable exogenous energy source such as glucose, fructose, lactate, or pyruvate and no stimulation occurred when no substrate was added or when acetate was used as substrate. The response of the spermatozoa to bicarbonate also depended on the presence of adequate concentrations of potassium (5 mM) and to a lesser extent magnesium (1 mM).Spermatozoa incubated with [14C]bicarbonate failed to incorporate any significant amount of radioactivity. Furthermore, the addition of C4 compounds in the form of malate or oxaloacetate failed to influence the response of the spermatozoa to bicarbonate. These results suggest that the stimulating effects of bicarbonate on boar spermatozoa are not mediated by way of CO2 fixation reactions which replenish the tricarboxylic acid cycle with C4 compounds. However, bicarbonate did stimulate respiration in the presence of various intermediates of the tricarboxylic acid cycle and it is possible, therefore, that the ion acts in boar spermatozoa to increase the activities of various enzymes of the tricarboxylic acid cycle, or to facilitate the transport of exogenous substrates into the cell, or both.