RESUMO
5'-nucleotidase [5'-NT] and Gamma glutamyl transferase [GGT] activity was measured in the tissues of four 2-6 years old donkeys; four 6-9 month old castrated male goats and four 6-9 month old male calves. In donkeys the lung is the richest source of the enzyme 5'-NT, whereas in goats the liver contains a higher activity of the enzyme compared with other species. Generally the values of 5'-NT activities in tissues of calves and goats are higher than those of donkeys. GGT is mainly located in the kidneys, pancreas and liver of all the species studied. 20-25% loss in activity of GGT occurred after thawing and freezing of tissues for 2 weeks whereas more than 50% loss in activity of the enzyme occurred in four weeks period. The fall in the activity of 5'-NT in tissues was not consistent in all tissues during the first two weeks, but after four weeks period 50% loss of activity was observed