Depletion of Riboflavin Contents in Subsarcolemmal and Intermyofibrillar Mitochondria of Canine Heart Muscle Affected by Ischemia

In dog heart mitochondria, the total flavin content was found to be higher in intermyofibrillar mitochondria (0.88 nmol per mg protein for FAD, 0.10 for FMN) than in subsarcolemmal mitochondria (0.27 for FAD, 0.07 far FMN). Sixty-minute occlusion of the coronary artery led to a decrease in FAD content in the ischemic region by approximately one-third. Glutathione reductase activity in subsarcolemmal mitochondria was depressed significantly by Ischemia. The activity coefficient increased to 1.36 from the control (1.07). Our results indicate that depletion of riboflavin content in mitochondria may be related to various metabolic alterations under ischemia and that riboflavin in subsarcolemmal mitochondria is influenced more by ischemia than that in intermyofibrillar ones.