Dissimilarity in oxygen consumption between the thoracic and abdominal aorta in rats.

Measurement of oxygen uptake by thoracic and abdominal segments of rat aorta showed significantly lower rates in the abdominal than in the thoracic aorta of adult animals. The evidence suggests that as a rat ages the respiratory rate of abdominal aorta falls more sharply than that of the thoracic segment. This result may provide an explanation for the relatively high incidence of atherosclerosis in abdominal aorta.