Influence of aging on adrenal responsiveness in a population of eleven healthy beagles

The present study aimed at investigating the effects of aging on the adrenal cortex response of cortisol and aldosterone in dogs. A population of healthy adult Beagles was evaluated twice at a five-year interval. At each evaluation, plasma basal cortisol and aldosterone, cortisol and aldosterone following ACTH-stimulation, sodium, and potassium concentrations and arterial blood pressure were measured. We observed significantly (p < 0.05) greater sodium, urea and creatinine concentrations with aging. Nevertheless urea and creatinine remained within our laboratory reference ranges. This study showed a highly significant age-related elevation of basal cortisol (p < 0.01). Inversely, both aldosterone following ACTH-stimulation levels and difference between aldosterone following ACTH-stimulation and basal aldosterone values plummeted significantly (p < 0.01) with aging. In conclusion, the evaluation of the adrenal cortex function in dogs should take in consideration the age of the individuals. (c) 2006 Elsevier Ltd. All rights reserved.