Granular pneumocytes and altitude: a stereological evaluation.

Stereological analysis demonstrates that the granular pneumocytes of mice native to high altitude (4660 m) are significantly larger than those of the same species (Phyllotis darwini) living at sea level. Such cells have larger nuclei and a significantly greater volume of mitochondria. There are both more and larger lamellar bodies in high altitude granular pneumocytes, resulting in about four times more surfactant per cell at high altitude.