Mitochondrial Changes Induced by Thyroid Hormones

Abstract
Incubation at 37 C of heavy suspensions of rat liver mitochondria results in release into the suspending medium of protein containing DPNH diaphorase activity. The addition of 5 × 1O-5M thyroxine produces a biphasic effect upon release kinetics, with an early acceleration and a late decrease in the process. Similar effects upon release kinetics are noted on incubation of liver mitochondria from severely thyrotoxic rats. The existence is proposed of liver mitochondria with different responses to thyroid hormone. (Endocrinology75: 770, 1964)