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Hepatorenal reflex in the rat
T A Meredith1, P H Brand, P J Metting
1Department of Physiology and Molecular Medicine, Medical College of Ohio, Toledo 43614, USA.
Canadian Journal of Physiology and Pharmacology
|April 16, 1998
Summary
The liver plays a crucial role in regulating sodium excretion after a high-salt meal. Hepatic denervation significantly reduced sodium excretion in rats, indicating a hepatorenal reflex.
Area of Science:
- Physiology
- Renal Physiology
- Gastrointestinal Physiology
Background:
- The existence of a hepatorenal reflex, a neural pathway connecting the liver and kidneys, is not fully understood.
- Understanding this reflex is important for comprehending sodium homeostasis and fluid balance.
Purpose of the Study:
- To investigate the role of the liver in postprandial sodium excretion.
- To evaluate the existence and function of a hepatorenal reflex in rats.
Main Methods:
- Male Sprague-Dawley rats were divided into two groups: hepatic denervation and sham denervation.
- Sodium excretion was measured hourly for 4 hours after consuming high-salt chow.
- Norepinephrine concentration in liver tissue was measured to confirm denervation completeness.
Main Results:
- Hepatic denervation significantly reduced sodium excretion by 91% in the first hour and 44% in the second hour post-ingestion (p < 0.02 and p < 0.04, respectively).
- Sham denervation did not significantly alter sodium excretion rates.
- Liver tissue norepinephrine levels were significantly lower in denervated rats (5.1 ± 8 ng/g) compared to sham rats (22.8 ± 1 ng/g, p < 0.001).
Conclusions:
- The liver is essential for normal postprandial sodium excretion following high-salt intake in rats.
- These findings support the existence of a hepatorenal reflex pathway influencing sodium handling.