Influence of non-steroidal anti-inflammatory compounds on the hepatic tryptophan pyrrolase activity in hypo- and hyperthyroid rats.

Hypothyroid state induced in the rat by thyroparathyroidectomy does not modify the activity of hepatic tryptophan pyrrolase (TPO) while hyperthyroidism, obtained after daily injection of 3, 3', 5-triiodo-L-thyronine, inhibits significantly the liver TPO activity. Treatment with oxametacine, indomethacin, phenylbutazone, flufenamic acid and acetylsalicylic acid, increases the activity of hepatic TPO in hypothyroid state, whereas, in hyperthyroid rats, the same drugs are able to restore the normal enzymatic activity, except for acetylsalicylic acid. During the development of an acute inflammatory process, provoked by carrageenan injection, the treatment with non-steroidal anti-inflammatory agents induces an enhancement of hepatic TPO activity. On the contrary, such enzymatic activity appears unaffected in chronic inflammation induced by cotton-pellet implantation.