Effects of hypophysectomy on amino acid metabolism and gluconeogenesis in the perfused rat liver

E. L. Tolman, C. M. Schworer, L. S. Jefferson

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

The effects of hypophysectomy on amino acid metabolism were studied both in vivo and in the perfused rat liver. Hypophysectomized rats exhibited elevated plasma urea concentration and reduced plasma and liver amino acid levels, while perfused livers from these animals showed enhanced rates of amino acid uptake. No effect of hypophysectomy on hepatic amino acid transport was noted, suggesting that the enhanced hepatic amino acid uptake resulted from an increased flux through the metabolic pathway (or pathways) operating in the liver. Livers from hypophysectomized rats produced substantially more glucose and urea than livers from normal animals when both were perfused with medium containing various levels of amino acids. The rate of glucose synthesis from either labeled alanine, pyruvate, glutamate, or aspartate was stimulated 3 to 4 fold in livers from hypophysectomized rats, showing an increased flux of amino acids through the pathway of gluconeogenesis. Treatment of hypophysectomized rats with growth hormone for 2 days returned the rate of gluconeogenesis from alanine toward normal, although the reversion was incomplete. The data suggested that the enhanced hepatic utilization of amino acids following hypophysectomy resulted from increased metabolism of the compounds in the liver, involving increased fluxes throuh the pathways of gluconeogenesis and ureogenesis.

Original languageEnglish (US)
Pages (from-to)4552-4560
Number of pages9
JournalJournal of Biological Chemistry
Volume248
Issue number13
StatePublished - Dec 1 1973

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Hypophysectomy
Gluconeogenesis
Metabolism
Liver
Rats
Amino Acids
Fluxes
Alanine
Urea
Animals
Plasmas
Glucose
Pyruvic Acid
Aspartic Acid
Growth Hormone
Glutamic Acid
Metabolic Networks and Pathways

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

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abstract = "The effects of hypophysectomy on amino acid metabolism were studied both in vivo and in the perfused rat liver. Hypophysectomized rats exhibited elevated plasma urea concentration and reduced plasma and liver amino acid levels, while perfused livers from these animals showed enhanced rates of amino acid uptake. No effect of hypophysectomy on hepatic amino acid transport was noted, suggesting that the enhanced hepatic amino acid uptake resulted from an increased flux through the metabolic pathway (or pathways) operating in the liver. Livers from hypophysectomized rats produced substantially more glucose and urea than livers from normal animals when both were perfused with medium containing various levels of amino acids. The rate of glucose synthesis from either labeled alanine, pyruvate, glutamate, or aspartate was stimulated 3 to 4 fold in livers from hypophysectomized rats, showing an increased flux of amino acids through the pathway of gluconeogenesis. Treatment of hypophysectomized rats with growth hormone for 2 days returned the rate of gluconeogenesis from alanine toward normal, although the reversion was incomplete. The data suggested that the enhanced hepatic utilization of amino acids following hypophysectomy resulted from increased metabolism of the compounds in the liver, involving increased fluxes throuh the pathways of gluconeogenesis and ureogenesis.",
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Effects of hypophysectomy on amino acid metabolism and gluconeogenesis in the perfused rat liver. / Tolman, E. L.; Schworer, C. M.; Jefferson, L. S.

In: Journal of Biological Chemistry, Vol. 248, No. 13, 01.12.1973, p. 4552-4560.

Research output: Contribution to journalArticle

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