Adenine nucleotide translocase, Na+-K+-and Mg2+-ATPases and differential tissue response to hypothyroidism.

The activities of adenine nucleotide translocase (ANT), Na+-K+-ATPase (EC 3.6.1.3) and Mg2+-ATPase (EC 3.6.1.3) together with mitochondrial marker enzymes, succinic dehydrogenase (EC 1.3.99.1) and glutamate dehydrogenase (EC 1.4.1.2), were measured in liver, kidney, brain and testis from normal and thyroidectomised rats. Na+-K+-ATPase decreased by approximately 50% in liver and kidney; ANT decreased only in liver (-40%) while the activity of ANT per gram kidney increased by 38%. The activity of Mg2+-ATPase closely correlated with the pattern of change of ANT. The hormonal and substrate regulation of ANT is discussed in relation to its role in the regulation of intracellular phosphate potential and compartmentation in liver and kidney.