Propranolol induced lipid accumulation and mitochondrial granularity in myocardial cells.

The ultrastructure of the left ventricular wall was studied in mice given intraperitoneal injections of propranolol (5 mg or 20 mg.kg-1 b.w. twice a day for 48 h with an additional dose 3 h before death), and in saline injected controls. Injections of propranolol increase the number of lipid droplets in areas of the myocardium. Fractional volume of lipid droplets in myocardial cells determined using quantitative stereological techniques, showed an increase of 280% and 544% in the group receiving the lowest and highest doses respectively. Injections of propranolol were also followed by an increased granularity of the mitochondria.