[Changes in the activity of histamine-liberating enzymes in acute experimental anaphylaxis]

The authors examined the changes in the histamine level, DAO (diaminoxidase) activity and N--MT (N-methyltransferase) activity in blood (plasma) and tissues of lung and liver (N--MT was examined only in the indicated tissues) in 105 guinea pigs, 45 of whom were healthy and 60 sensibilised and examined during the anaphylactic shock. It was established that during the acute anaphylactic shock there was demonstrative hyperhistanemia and hyperhistaminasemia, which were not observed during experimental anaphylactic shock with subacute course. The activity of lung and liver N--MT in animals with acute and subacute anaphylactic shock did not differ from that of the healthy guinea pigs. The complete inhibition of DAO activity in healthy animals and those with anaphylactic shock did not induce change in the activity of N--MT as well. The latter did not alter after sharp or high level or moderate elevation of the tissue histamine for several days. This histamine was a specific substrate for this enzyme. N--MT is an inductive enzyme, which apparently does not participate in histamine metabolism during acute and subacute anaphylaxis in guinea pigs. For its change, probably, is necessary longer time.