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Plasma hormone and renal function changes in unrestrained dogs exposed to cold
The American Journal of Physiology
|February 1, 1975
Summary
Cold exposure in dogs affects antidiuretic hormone (ADH) and norepinephrine levels, but not plasma cortisol, influencing urine concentration differently in unrestrained versus restrained animals.
Area of Science:
- Physiology
- Endocrinology
- Environmental Medicine
Background:
- Cold exposure can alter hormonal balance and renal function.
- Previous studies suggested a role for cortisol in cold-induced urine concentration defects, primarily in restrained animals.
Purpose of the Study:
- To investigate the physiological responses to cold ambient temperatures in unrestrained dogs.
- To examine the roles of antidiuretic hormone (ADH), 17-hydroxycorticoids, and norepinephrine in cold adaptation.
- To determine if plasma cortisol elevation is critical for the urine concentration defect observed in cold.
Main Methods:
- Measurements of renal clearances, plasma ADH, 17-hydroxycorticoids, and norepinephrine in unrestrained dogs.
- Experimental groups included controls, Metopirone (cortisol synthesis inhibitor), and Metopirone with dexamethasone (ACTH suppressor).
- Dogs were exposed to ambient cold ( -4 to +4°C).
Main Results:
- Plasma ADH increased significantly in Metopirone-treated dogs but not others.
- Plasma 17-hydroxycorticoids rose in untreated dogs during cold exposure.
- Plasma norepinephrine increased, and cold exposure altered spontaneous urine flow tendencies, particularly in Metopirone-dexamethasone treated dogs.
Conclusions:
- Plasma cortisol elevation is not essential for the urine concentration defect in cold.
- Unrestrained dogs exhibit distinct physiological responses to cold compared to restrained animals.
- Cold exposure impacts ADH and norepinephrine, influencing renal function independently of significant cortisol changes.