Mode of death effect on rat liver iodothyronine 5' deiodinase activity: role of adenosine 3',5' monophosphate.

Liver thyronine 5'-deiodinase activity assayed in crude homogenates in the absence of dithiothreitol (DTT) is increased in rats killed by asphyxia when compared to that of animals killed by phenobarbital injection or decapitation. The addition of cyclic adenosine monophosphate leads to a consistent decrease in observed deiodinase activity, suggesting the possible involvement of this nucleotide in the regulation of this enzyme. The addition of DTT eliminates this effect and suggest a dual regulation of the enzyme by cAMP and physiological sulfhydryl compounds.