Abstract des Autors

Male Wistar rats were subjected daily to a swimming exercise for thirty days. The surface tension of alveolar surfactant preparations and biochemical variables were measured 10, 20 and 30 days after the beginning of swimming. Time changes in the activity of alveolar lining complex surface had a distinct pattern with an initial increase, near-control level on Day 20, and an increase on Day 30. These changes were associated with temporary predominance of non-polar (phospholipids, free cholestrol) or polar (total proteins, beta-lipoproteins) compounds in the alveolar surfactant complex. As follows from correlation coefficients, the increases in surface activity may be due to an excess of surfactant phospholipids and free cholesterol in the surfactant complex of trained animals, while a temporary normalization of surface activity may be accounted for by an elevated concentration of proteins and beta-lipoproteins. In the phospholipid composition of trained animals, increased contents of both saturated and polyunsaturated fatty acids, especially palmitate and arachidonate, were found. The increased surface activity of alveolar surfactant may be regarded as a possible physiological mechanism serving probably both the extention of internal volume of alveoli and adaptation of pulmonary ventilation to exercise in trained adult rats. Verf.-Referat