THE PROLIFERATIVE ACTIVITY OF MYOCARDIAL CAPILLARY WALL CELLS IN VARIOUSLY AGED SWIMMING-EXERCISED RATS

Cellular proliferation was studied by incorporation of 3H-thymidine in the hearts of young, adult and old swimming-exercised rats. The proliferative activity was measured by scintillation counting. The swimming exercise induced a significant proliferation of capillary wall cells in the younger age groups, suggesting a neoformation of myocardial capillaries in these rats, whereas no cell proliferation was recorded in the old rats.