Abstract: | Myocardial hypertrophy was induced in rats and mice by training in the pressure chamber (high altitude hypoxia) or ligation of the apex of the heart. Transversely oriented myofibrils developed in the subsarcolemma area of some cardiomyocytes of the ventricles in a fortnight; the Z bands of the newly-formed myofibrils were connected with the T tubules as in the normal myofibrils. It is supposed that this phenomenon was due to the appearance under the sarcolemma of transversely directed mechanical forrces as a result of enlargement of the cell volume. |