The effect of stress or glucose feeding on hepatic tyrosine aminotransferase activity and liver and plasma tyrosine level of intact and adrenalectomized rats.

The increase of hepatic tyrosine aminotransferase and the fall of plasma tyrosine in rats subjected to immobilization is reconfirmed. Moreover, the same effects three hrs after exposuing the animals to 400 revolutions in Noble-Collip drums are described. However, in bilaterally adrenalectomized rats both hepatic tyrosine aminotransferase and plasma tyrosine remain unchanged after injury and the liver tyrosine level increase. Finally, in animals fed overnight exclusively with 15% glucose solution the well-known decrease of hepatic tyrosine aminotransferase was found paralleled by increased plasma tyrosine levels. A regulatory role of tyrosine aminotransferase in establishing the level of tyrosine in plasma is suggested.