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Cold exposure regulates the renin-angiotensin system
L Cassis1, A Laughter, M Fettinger
1Division of Pharmacology and Experimental Therapeutics, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536-0082, USA.
The Journal of Pharmacology and Experimental Therapeutics
|August 8, 1998
Summary
Cold exposure increases plasma angiotensin II (Ang II) and its receptor density in specific tissues. Increased food intake drives these changes, but Ang II receptor regulation is independent of plasma Ang II levels.
Area of Science:
- Physiology
- Endocrinology
- Metabolism
Background:
- Cold exposure impacts the body's systems, including the renin-angiotensin system.
- Understanding angiotensin II (Ang II) receptor regulation is crucial for metabolic and cardiovascular health.
Purpose of the Study:
- To investigate the effect of cold exposure on the renin-angiotensin system and Ang II receptor regulation.
- To examine Ang II receptor changes in cardiovascular and metabolic tissues during cold adaptation.
Main Methods:
- Rats were exposed to cold (4°C) for varying durations (4 hours to 7 days).
- Plasma Ang II concentrations and Ang II receptor binding characteristics (affinity, density) were measured in liver, ISBAT, kidney, and left ventricle.
- Pair-feeding experiments were conducted to assess the role of increased food intake.
Main Results:
- Plasma Ang II concentration fluctuated, with peaks at 4 hours and 7 days of cold exposure.
- Ang II receptor density increased in liver, ISBAT, kidney, and left ventricle, but not lung.
- Increased food intake contributed to elevated plasma Ang II and receptor density, but receptor upregulation was not directly mediated by plasma Ang II levels.
Conclusions:
- Cold exposure alters plasma Ang II and upregulates Ang II receptors in a tissue-specific manner.
- Increased food intake associated with cold exposure plays a role in these adaptations.
- Ang II receptor density changes are not solely dependent on circulating Ang II concentrations.