Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 1981 Jun 15;196(3):757–762. doi: 10.1042/bj1960757

Utilization of L-alanine and L-glutamine by lactating mammary gland of the rat. A role for L-alanine as a lipogenic precursor.

J R Viña, D H Williamson
PMCID: PMC1163095  PMID: 7317014

Abstract

1. Lactation is associated with an increase in the arterial blood concentration of L-alanine and L-glutamate, but a decrease in that of L-glutamine compared with the corresponding values for virgin rats. 2. Virgin rats fed a 'cafeteria diet' that induces hyperphagia have increased arterial concentrations of L-alanine, L-glutamate and L-glutamine. During lactation L-alanine and L-glutamate concentrations are even higher. 3. The removal of L-alanine is decreased in hepatocytes from lactating rats fed either a chow or cafeteria diet. 4. Measurements of arteriovenous differences across lactating mammary glands indicate that appreciable amounts of L-glutamine and L-alanine are extracted by the gland. 5. A high proportion of the L-alanine metabolized by isolated acini from fed lactating rats is converted into lipid. 6. Metabolism of L-alanine in acini from starved lactating rats is limited by the activity of pyruvate dehydrogenase. 7. It is concluded that L-alanine and certain other amino acids taken up by the gland in excess of the requirements for protein synthesis can be converted into lipid.

Full text

PDF

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ABRAHAM S., MADSEN J., CHAIKOFF I. L. THE INFLUENCE OF GLUCOSE ON AMINO ACID CARBON INCORPORATION INTO PROTEINS, FATTY ACIDS, AND CARBON DIOXIDE BY LACTATING RAT MAMMARY GLAND SLICES. J Biol Chem. 1964 Mar;239:855–864. [PubMed] [Google Scholar]
  2. Amenomori Y., Chen C. L., Meites J. Serum prolactin levels in rats during different reproductive states. Endocrinology. 1970 Mar;86(3):506–510. doi: 10.1210/endo-86-3-506. [DOI] [PubMed] [Google Scholar]
  3. Baxter M. A., Coore H. G. The mode of regulation of pyruvate dehydrogenase of lactating rat mammary gland. Effects of starvation and insulin. Biochem J. 1978 Aug 15;174(2):553–561. doi: 10.1042/bj1740553. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Berry M. N., Friend D. S. High-yield preparation of isolated rat liver parenchymal cells: a biochemical and fine structural study. J Cell Biol. 1969 Dec;43(3):506–520. doi: 10.1083/jcb.43.3.506. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chatwin A. L., Linzell J. L., Setchell B. P. Cardiovascular changes during lactation in the rat. J Endocrinol. 1969 Jun;44(2):247–254. doi: 10.1677/joe.0.0440247. [DOI] [PubMed] [Google Scholar]
  6. FELL B. F., SMITH K. A., CAMPBELL R. M. Hypertrophic and hyperplastic changes in the alimentary canal of the lactating rat. J Pathol Bacteriol. 1963 Jan;85:179–188. doi: 10.1002/path.1700850117. [DOI] [PubMed] [Google Scholar]
  7. FELLER D. D., FEIST E. Metabolism of alanine, serine and valine in adipose tissue. Metabolism. 1962 Apr;11:448–455. [PubMed] [Google Scholar]
  8. Felig P., Pozefsky T., Marliss E., Cahill G. F., Jr Alanine: key role in gluconeogenesis. Science. 1970 Feb 13;167(3920):1003–1004. doi: 10.1126/science.167.3920.1003. [DOI] [PubMed] [Google Scholar]
  9. HOHORST H. J., KREUTZ F. H., BUECHER T. [On the metabolite content and the metabolite concentration in the liver of the rat]. Biochem Z. 1959;332:18–46. [PubMed] [Google Scholar]
  10. Hanson P. J., Parsons S. Metabolism and transport of glutamine and glucose in vascularly perfused small intestine rat. Biochem J. 1977 Sep 15;166(3):509–519. doi: 10.1042/bj1660509. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kankel K. F., Reinauer H. Activity of pyruvate dehydrogenase complex in the mammary gland of normal and diabetic rats. Diabetologia. 1976 May;12(2):149–154. doi: 10.1007/BF00428981. [DOI] [PubMed] [Google Scholar]
  12. Katz J., Wals P. A., Van de Velde R. L. Lipogenesis by acini from mammary gland of lactating rats. J Biol Chem. 1974 Nov 25;249(22):7348–7357. [PubMed] [Google Scholar]
  13. Lund P. Glutamine metabolism in the rat. FEBS Lett. 1980 Aug 25;117 (Suppl):K86–K92. doi: 10.1016/0014-5793(80)80573-4. [DOI] [PubMed] [Google Scholar]
  14. MacDonald M., Neufeldt N., Park B. N., Berger M., Ruderman N. Alanine metabolism and gluconeogenesis in the rat. Am J Physiol. 1976 Aug;231(2):619–626. doi: 10.1152/ajplegacy.1976.231.2.619. [DOI] [PubMed] [Google Scholar]
  15. Mallet L. E., Exton J. H., Park C. R. Control of gluconeogenesis from amino acids in the perfused rat liver. J Biol Chem. 1969 Oct 25;244(20):5713–5723. [PubMed] [Google Scholar]
  16. Robinson A. M., Williamson D. H. Comparison of glucose metabolism in the lactating mammary gland of the rat in vivo and in vitro. Effects of starvation, prolactin or insulin deficiency. Biochem J. 1977 Apr 15;164(1):153–159. doi: 10.1042/bj1640153. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Robinson A. M., Williamson D. H. Control of glucose metabolism in isolated acini of the lactating mammary gland of the rat. The ability of glycerol to mimic some of the effects of insulin. Biochem J. 1977 Dec 15;168(3):465–474. doi: 10.1042/bj1680465. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Rolls B. J., Rowe E. A., Turner R. C. Persistent obesity in rats following a period of consumption of a mixed, high energy diet. J Physiol. 1980 Jan;298:415–427. doi: 10.1113/jphysiol.1980.sp013091. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Rémésey C., Demigné C., Aufrère J. Inter-organ relationships between glucose, lactate and amino acids in rats fed on high-carbohydrate or high-protein diets. Biochem J. 1978 Feb 15;170(2):321–329. doi: 10.1042/bj1700321. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Sclafani A., Springer D. Dietary obesity in adult rats: similarities to hypothalamic and human obesity syndromes. Physiol Behav. 1976 Sep;17(3):461–471. doi: 10.1016/0031-9384(76)90109-8. [DOI] [PubMed] [Google Scholar]
  21. Snell K. Muscle alanine synthesis and hepatic gluconeogenesis. Biochem Soc Trans. 1980 Apr;8(2):205–213. doi: 10.1042/bst0080205. [DOI] [PubMed] [Google Scholar]
  22. Stansbie D., Brownsey R. W., Crettaz M., Denton R. M. Acute effects in vivo of anti-insulin serum on rates of fatty acid synthesis and activities of acetyl-coenzyme A carboxylase and pyruvate dehydrogenase in liver and epididymal adipose tissue of fed rats. Biochem J. 1976 Nov 15;160(2):413–416. doi: 10.1042/bj1600413. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Viña J. R., Williamson D. H. Effects of lactation on L-leucine metabolism in the rat. Studies in vivo and in vitro. Biochem J. 1981 Mar 15;194(3):941–947. doi: 10.1042/bj1940941. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Viña J., Puertes I. R., Estrela J. M., Viña J. R., Galbis J. L. Involvement of gamma-glutamyltransferase in amino-acid uptake by the lactating mammary gland of the rat. Biochem J. 1981 Jan 15;194(1):99–102. doi: 10.1042/bj1940099. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Watford M., Lund P., Krebs H. A. Isolation and metabolic characteristics of rat and chicken enterocytes. Biochem J. 1979 Mar 15;178(3):589–596. doi: 10.1042/bj1780589. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Whitehouse S., Cooper R. H., Randle P. J. Mechanism of activation of pyruvate dehydrogenase by dichloroacetate and other halogenated carboxylic acids. Biochem J. 1974 Sep;141(3):761–774. doi: 10.1042/bj1410761. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Whitehouse S., Randle P. J. Activation of pyruvate dehydrogenase in perfused rat heart by dichloroacetate (Short Communication). Biochem J. 1973 Jun;134(2):651–653. doi: 10.1042/bj1340651. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Williamson D. H., Lopes-Vieira O., Walker B. Concentrations of free glucogenic amino acids in livers of rats subjected to various metabolic stresses. Biochem J. 1967 Aug;104(2):497–502. doi: 10.1042/bj1040497. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Williamson D. H., McKeown S. R., Ilic V. Interactions of glucose, acetoacetate and insulin in mammary-gland slices of lactating rats. Biochem J. 1975 Aug;150(2):145–152. doi: 10.1042/bj1500145. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Windmueller H. G., Spaeth A. E. Identification of ketone bodies and glutamine as the major respiratory fuels in vivo for postabsorptive rat small intestine. J Biol Chem. 1978 Jan 10;253(1):69–76. [PubMed] [Google Scholar]
  31. Windmueller H. G., Spaeth A. E. Intestinal metabolism of glutamine and glutamate from the lumen as compared to glutamine from blood. Arch Biochem Biophys. 1975 Dec;171(2):662–672. doi: 10.1016/0003-9861(75)90078-8. [DOI] [PubMed] [Google Scholar]
  32. Windmueller H. G., Spaeth A. E. Vascular perfusion of rat small intestine: metabolic studies with isolated and in situ preparations. Fed Proc. 1977 Feb;36(2):177–181. [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES