Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-25T06:38:25.754Z Has data issue: false hasContentIssue false

Effects of pregnancy and lactation on the activities in sheep liver of some enzymes of glucose metabolism

Published online by Cambridge University Press:  27 March 2009

R. W. Smith
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT
Ann Walsh
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, RG2 9AT

Summary

The activities of some enzymes that regulate the gluconeogenic-glycolytic pathway were measured in sheep liver during late pregnancy, at three stages of lactation and after the lambs were weaned. Of the gluconeogenic enzymes, glucose-6-phosphatase and phosphoenolpyruvate carboxylase activities were unchanged throughout pregnancy and lactation and were similar to the values for non-breeding ewes. The activity of fructose diphosphatase increased 2 times and that of pyruvate carboxylase increased 5–7 times during late pregnancy and in early lactation.

In the glycolytic sequence phosphofructokinase activity declined by about 50% during lactation. Pyruvate kinase activity declined by about 40% at the end of pregnancy but throughout lactation it was similar to the value for non-breeding ewes. Hexokinase activity was very low in all animals.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1982

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Baird, G. D. & Heitzman, R. J. (1970). Gluconeogenesis in the cow. The effects of a glucocorticoid on hepatic intermediary metabolism. Biochemical Journal 116, 865874.CrossRefGoogle ScholarPubMed
Baird, G. D., Lomax, M. A., Symonds, H. W. & Shaw, S. R. (1980). Net hepatic and splanchnic metabolism of lactate, pyruvate and propionate in dairy cows in vivo in relation to lactation and nutrient supply. Biochemical Journal 186, 4757.CrossRefGoogle ScholarPubMed
Ballard, F. J., Hanson, R. W. & Kronfeld, D. S. (1969). Gluconeogenesis and lipogenesis in tissues from ruminant and non-ruminant animals. Federation Proceedings 28, 218231.Google Scholar
Leng, R. A. (1970). Glucose synthesis in ruminants. Advances in Veterinary Science 14, 209260.Google ScholarPubMed
Mackie, W. S. & Campbell, R. M. (1972). Effects of pregnancy and lactation on the activities of some gluconeogenic and urea-cycle enzymes in sheep liver. Journal of Agricultural Science, Cambridge 79, 423429.CrossRefGoogle Scholar
Smith, R. W. (1973). The effects of pregnancy, lactation and involution on the metabolism of glucose and acetate by rat liver tissue. Journal of Dairy Research 40, 339351.CrossRefGoogle Scholar
Smith, R. W. (1975). The effects of pregnancy and lactation on the activities in rat liver of some enzymes associated with glucose metabolism. Biochimica et Biophysica Acta 404, 2229.CrossRefGoogle Scholar
Steel, J. W. & Leng, R. A. (1973). Effects of plane of nutrition and pregnancy on gluconeogenesis in sheep. 2. Synthesis of glucose from ruminal propionate. British Journal of Nutrition 30, 475489.CrossRefGoogle ScholarPubMed
Weekes, T. E. C. & Webster, A. J. F. (1975). Metabolism of propionate in the tissues of the sheep gut. British Journal of Nutrition 33, 425438.CrossRefGoogle Scholar
Young, J. W. (1977). Gluconeogenesis in cattle: significance and methodology. Journal of Dairy Science 60, 115.CrossRefGoogle ScholarPubMed