Age-related changes in the catecholamine content of peripheral organs in male and female F344 rats

Norepinephrine levels of old and young F344 rats of both sexes were compared in several organs that receive sympathetic innervation. In addition, both norepinephrine and epinephrine concentrations in the adrenal medulla of young and old rats were determined. A rationale was developed for making age-related comparisons of the catecholamine content in peripheral organs which accounted for age-related changes in organ weight and body weight. It was found that norepinephrine concentrations were decreased for old male rats in heart auricles. In contrast, in old female rats there were no age-related changes in the catecholamine content of any peripheral organ.