Regression of autophagic vacuoles in mouse pancreatic cells: a morphometric study of the effect of methylamine and chloroquine followed by cycloheximide treatment.

Treatment of mice with methylamine and chloroquine for two hours markedly increased the volume fraction of autophagic vacuoles in the pancreatic acinar cells of the mouse. The autophagic vacuoles disappeared from the cells within 20 min after the administration of a suppressor of autophagic sequestration cycloheximide to animals pretreated with 0.25 mg b.w. dose of methylamine. In contrast, no regression or very slow decay was seen in cells of mice pretreated with higher doses of methylamine (0.50-0.70 mg/g b.w.) and chloroquine (0.08 mg/g b.w.). Our data show that the two drugs retard the disintegration of autophagic vacuole content. It is concluded, that accumulation of autophagic vacuoles due to their slow turnover is an important mechanism of the expansion of autophagic vacuole compartment under the effect of methylamine and chloroquine.