[The clinical significance of changes in lung function, oxygen consumption and some bio-active substances in...

Lung function was assayed in 40 healthy adults who moved to high altitude area (Lhasa, 3,658 m above sea level, Group A) recently and 160 who had lived for a long period of time (Group B). Oxygen consumption was also measured and serum triiodothyronine (T3), thyroxin (T4), reverse triiodothyronine (rT3), endogenous digitalis factors (EDF), plasma renin activity (PRA), angiotensin II (AII), aldosterone (ALD) and the concentration of atrial natriuretic peptide (ANP) were determined with radioimmunoassay in 80 of them. The results showed: (1) In both groups, lung volume was increased, flow rate of ventilation markedly quickened and diffusion enhanced as compared with the normal value; (2) Thyroid function was reduced; (3) ANP and EDF were markedly increased and ALD was reduced. AII was markedly increased and PRA was normal in Group A but on the contrary in Group B. The possible relation of these changes with the length of time of stay at high altitude is discussed.