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Increased adrenomedullin expression in lungs in endotoxaemia
B M Y Cheung1, I S S Hwang, C Y Y Li
1Department of Medicine, University of Hong Kong, Hong Kong, China. mycheung@hkucc.hku.hk
The Journal of Endocrinology
|May 7, 2004
Summary
Endotoxin (lipopolysaccharide) significantly increases adrenomedullin (AM) levels in the blood and lungs of rats. This peptide may play a role in the body's response to sepsis.
Area of Science:
- Endocrinology
- Immunology
- Physiology
Background:
- Adrenomedullin (AM) is a peptide hormone critical for maintaining cardiovascular homeostasis and regulating inflammatory responses.
- Sepsis, a life-threatening condition often triggered by bacterial endotoxins, involves complex systemic inflammatory processes.
Purpose of the Study:
- To investigate the impact of endotoxaemia on adrenomedullin expression and concentration in a rat model.
- To elucidate the role of AM in the physiological response to lipopolysaccharide (LPS) challenge.
Main Methods:
- Male Sprague-Dawley rats were administered varying doses of lipopolysaccharide (LPS) or saline.
- Blood and lung tissue samples were collected at multiple time points post-injection (1, 3, 6, 12, and 24 hours).
- Plasma AM concentrations and lung prepro-AM mRNA levels were quantified.
Main Results:
- LPS administration significantly elevated plasma AM levels in a dose- and time-dependent manner.
- Lung immunoreactive AM concentration and prepro-AM mRNA levels were markedly increased following LPS exposure.
- Control saline injections did not elicit significant changes in AM levels.
Conclusions:
- Endotoxin exposure stimulates both the expression and circulating levels of adrenomedullin in rats.
- Adrenomedullin is implicated in the systemic inflammatory response during endotoxaemia and may be a key mediator in sepsis.