Inhibition of pinocytosis and induction of release of lysosomal contents by lysosomal overload of arterial smooth muscle cells in vitro.

Lysosomal overload was induced experimentally in cultured aortic smooth muscle cells by incubation with chloroquine or sucrose. Lysosomal overload was accompanied by a marked reduction in pinocytosis and induced the release of lysosomal contents into the medium. Thus, previously accumulated pinocytic tracer and beta-glucuronidase, a lysosomal enzyme, were released into the medium whereas lactate dehydrogenase, a cytosolic enzyme, was not.