[An attempt at assessment of biotransformation activity in calves' liver on the basis of the rate of antipyrine elimination from saliva].

In the test carried out on 10 calves-bulls of c.b. breed, aged 20-23 days, the usefulness of the rate of antipyrine elimination from saliva to the assessment of pharmacokinetics of this substance, and consequently to the assessment of the rate of liver biotransformation in these animals, was defined. It was stated that volume of antipyrine (phenazone) distribution, half-life period and the clearance of liver defined on the basis of determination of the changes of phenazone concentration in plasma and saliva are not significantly different. It was proved that in the neonatal period in calves the antipyrine fraction connected with plasma protein does not exceed 3 percent of general phenazone concentration in the plasma. On the grounds of the results of the antipyrine test carried out a second time on 5 calves, the frequent recurrence of the parameters of antipyrine kinetics in the tested animals was proved. The results of the experimental show that on the basis of determination of the phenazone concentration in saliva it is possible to define the biotransforming liver activity of the microsomal monoxygenase connected with cytochrome P-450 in calves and total water content in the organism.