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Adrenergic blockade attenuates endotoxin-induced hepatic glucose uptake
A Ottlakán1, Z Spolarics, C H Lang
1Department of Physiology, Louisiana State University Medical Center, New Orleans 70112.
Circulatory Shock
|January 1, 1993
Summary
This study reveals that catecholamines partially mediate the endotoxin-induced increase in glucose uptake, particularly in the liver, by influencing plasma glucose levels. Adrenergic blockade affects glucose metabolism in endotoxemic animals.
Area of Science:
- Physiology
- Endocrinology
- Pharmacology
Background:
- Sepsis, often caused by endotoxins like lipopolysaccharide (LPS), triggers significant metabolic changes.
- The role of catecholamines in modulating glucose metabolism during endotoxemia requires further elucidation.
Purpose of the Study:
- To investigate the involvement of catecholamines in the endotoxin-induced enhancement of glucose uptake in various tissues.
- To determine the specific mechanisms by which adrenergic signaling influences tissue glucose utilization following LPS administration.
Main Methods:
- In vivo glucose utilization was measured using the 2-deoxyglucose tracer technique in rats injected with Escherichia coli lipopolysaccharide (LPS) or saline.
- Catecholamine action was blocked using combined alpha and beta adrenergic antagonists (phentolamine and propranolol).
- Plasma glucose levels and tissue glucose metabolic rate (Rg) and metabolic clearance rate (MCR) were assessed.
Main Results:
- LPS significantly increased Rg and MCR in multiple tissues, including the liver, lung, spleen, intestine, skin, fat, muscle, and kidney, but not the brain or testes.
- Adrenergic blockade completely abolished the LPS-induced Rg increase in the liver and partially inhibited it in other tissues.
- While adrenergic blockade attenuated LPS-induced Rg, it did not alter MCR in most tissues, except the liver, where both Rg and MCR were significantly reduced.
Conclusions:
- Catecholamines partially mediate the endotoxin-induced increase in tissue glucose utilization, with a pronounced effect on the liver.
- The observed changes in glucose metabolism during endotoxemia are influenced by both direct adrenergic effects and LPS-induced alterations in plasma glucose concentration.