Endotoxin Stimulates Lymphocyte Glutaminase Expression

Peter Sarantos, MD; Kimberly Ockert; Wiley W. Souba, MD, ScD
Arch Surg. 1993;128(8):920-924. doi:10.1001/archsurg.1993.01420200094017.
Text Size: A A A
Published online

Background/Hypothesis:  Glutamine is the principal fuel used by lymphocytes. It is hydrolyzed by the glutaminase enzyme, which regulates the rate of intracellular glutamine metabolism. Since lymphocyte glutamine utilization is increased during infection to support cellular proliferation, we hypothesized that endotoxin regulates lymphocyte glutaminase expression at the molecular level.

Methods:  Adult rats received Escherichia coli endotoxin (one dose of 7.5 mg/kg) or saline. Total RNA from lymphocytes in the ileocolic lymph node chain was extracted for Northern hybridization and labeled with an α–phosphorus 32 rat glutaminase cDNA probe. The mRNA of the constitutively expressed gene β-actin was the control for RNA loading. Quantitation of glutaminase transcripts was determined by densitometric scanning and values were normalized to actin. Glutaminase-specific activity (nanomoles per milligram of protein per hour) and glutaminase kinetic parameters were also determined.

Results:  Treatment with a single dose of endotoxin resulted in a 53% increase in glutaminase activity at 4 hours. Kinetic analysis showed that the increase in glutaminase activity was due to an 84% increase in Vmax (maximal enzyme velocity) with no change in Km (enzyme affinity). Endotoxin increased glutaminase mRNA twofold at 2 hours and more than fourfold at 4 hours. The increase in message preceded the increase in activity consistent with gene transcription prior to enzyme biosynthesis.

Conclusion/Clinical Relevance:  The increase in glutaminase activity provides lymphocytes in the mesenteric lymph nodes with more glutamine for energy and cellular proliferation during times of infection when the gut mucosal barrier may become compromised.(Arch Surg. 1993;128:920-924)


Sign In to Access Full Content

Don't have Access?

Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more

Subscribe for full-text access to content from 1998 forward and a host of useful features

Activate your current subscription (AMA members and current subscribers)

Purchase Online Access to this article for 24 hours





Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).
Submit a Comment


Some tools below are only available to our subscribers or users with an online account.

Sign In to Access Full Content

Related Content

Customize your page view by dragging & repositioning the boxes below.