Concerning the decreased D-3-hydroxybutyrate dehydrogenase activity in the liver and heart of hyperthyroid rats

Whereas in rat liver mitochondria the hyperthyroid state causes an increase both in fatty acid unsaturation and in the Ea of D-3-hydroxybutyrate dehydrogenase and a decrease in phase transition temperature, in hyperthyroid rat heart mitochondria these changes are negligible. D-3-hydroxybutyrate dehydrogenase in both the liver and the heart mitochondria of hyperthyroid rats is reduced by about 35% [12] but this reduction is not due to changes in membrane fluidity in either tissue. Hypothyroidism, on the other hand, affects BDH activity in neither heart nor liver.