Quantitative lung morphology in Japanese waltzing mice.

We have reinvestigated the question of whether exercise stimulates lung growth by determining body weight (BW), lung volume (LV), alveolar surface area (SA), and alveolar number (N) in Japanese waltzing mice, in their phenotypically normal littermates, and in normal albino mice. BW, LV, SA, and N were all less in waltzing mice than in their littermates; LV/BW, SA/BW, and N/BW were indistinguishable in the two groups. Age-matched albino mice had larger BW and smaller N/BW than the waltzers or their littermates. The results indicate that both waltzing mice and their nonwaltzing littermates have more highly compartmentalized lungs than albino mice of the same age. However, the data provide no support for the hypothesis that sustained exercise enhances lung growth.