Influence of thyroid hormone treatment on the respiratory activity of cerebral mitochondria from hypothyroid rats. A critical re-assessment

Effects of treatment with thyroid hormones L-3,5,3'-tri-iodothyronine (T-3) and L-thyroxine (T-4) on oxidative energy metabolism in cerebral mitochondria from hypothyroid adult rats were examined. It was observed that T-3 and T-4 stimulated respiratory activity in a substrate-specific and dose-dependent manner. The results also suggest that the synthesis of cytochrome aa(3) and of cytochrome c may be dependent on both T-3 as well as T-4 whereas higher concentrations than normal of T-3 and T-4 may have a catabolic influence on cytochrome b content. (c) 2005 Elsevier Inc. All rights reserved.