Seasonal variations of antipyrine pharmacokinetics parameters in calves.

In the experiment the values of parameters of antipyrine kinetics were defined (Vd - volume of distribution, t0.5 - half-life, CA - metabolic clearance) in calves in January, April, July and October 1986 and in January and July 1987. Statistically significant increase of distribution volume and increase of hepatic antipyrine clearance were recorded, as well as significant shortening of half-life of this substance in the organism of tested animals in summer 1986 and 1987, compared with the remaining seasons of the year. Antipyrine pharmacokinetics in winter, spring, autumn 1986 and winter 1986/87 did not differ significantly.

Pharmacokinetics of antipyrine in calves during first 35 days of life.

The experiment was carried out on 10 bull-calves of black-white breed, aged 2-35 days. The following parameters of antipyrine pharmacokinetics were determined: Vd - volume of distribution, t0.5 - biological half-life, CA - metabolic clearance. It has been shown statistically that the volume of antipyrine distribution (expressed in 1/kg) was significantly decreasing with age of examined animals. The antipyrine half-life proved to be the longest on the 20th day of calves' life and the shortest on the 10th and 30th day. The maximum values of metabolic clearance of antipyrine were observed in calves aged 10 days and the minimum ones in animals aged 20 days. In the cases of t0.5 and CA a tendency to changes of values of these parameters of antipyrine pharmacokinetics in 10 days periods was observed.

Monthly variations in the pharmacokinetics of antipyrine in calves.

In the experiment (on the basis of values of antipyrine (phenazone) pharmacokinetics parameter), biotransformation activity of calves liver during a year was determined. The experiment was carried out on calves aged 28-30 days. Volume of distribution (Vd), half-life (t0.5) and metabolic clearance (CA) of antipyrine were from month to month determined. Not significant changes between values of Vd, t0.5 and CA in several months were observed. Results of experiment indicated that calves' liver is characterized by the relatively stabile biotransformational activity during the whole year.

[Twenty-four hour changes in the value of the liver clearance of antipyrine in calves during the neonatal period]. / Dobowe zmiany wielkosci watrobowego klirensu antypiryny u cielat w okresie neonatalnym.

Twenty-four-hour changes in the value of the liver clearance coefficient of antipyrine in 10 calves of ncb. race, aged 28-30 days were examined. The findings made it possible to separate 2 subgroups among the examined animals: 6 calves eliminated antipyrine from plasma more quickly during the day than at night and 4 calves - more quickly at night than in the day. To verify the observed differences 3 days after the first examination another antipyrine test was performed on 6 calves (3 from the "night" group and 3 from the "day" group). It has been found that animals which had the tendency to quicker elimination (metabolism) of the antipyrine during the day confirmed it in the second examination. The same regularity has been observed for the calves which quicker eliminate antipyrine from plasma at night.

[An attempt at assessment of biotransformation activity in calves' liver on the basis of the rate of antipyrine elimination from saliva]. / Próba oceny biotransformacyjnej aktywnosci watroby u cielat na podstawie tempa eliminowania antypiryny ze sliny.

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.

[Effect of hypophysin and desoxycorticosterone acetate on kidney function in 3-month-old calves]. / Wplyw hipofizyny i octanu dezoksykortykosteronu na czynnosc nerek u trzymiesiecznych cielat.

The experiment has been carried out on 6 bulls of cb. breed at the age of 3 months. Clearance methods were used to examine the hypophysin (0.1 u V/kg) and desoxycorticosterone acetate (0.1 mg/kg) influence on the size of diuresis, glomerular filtration and excretion of the following: sodium, potassium, chlorides, calcium, magnesium and inorganic phosphorus with urine. Three months old calves had (in comparing to calves in neonatal period) higher glomerular filtration level and lower coefficient of endogenous creatinine purification, however the GFR did not still reach the GFR level of adult animals. Hypophysin and desoxycorticosterone acetate influenced both the process of glomerular filtration (decrease) and tubular transportation of water, Na, K and Cl. After the acetate had been applied, higher condensation of urine was noticed than after the application of hypophysin. Administering DOC to the calves caused decrease in sodium and chlorides excretion with urine as well as increase in kidney purification of potassium. Increased excretion of potassium ion and the decrease in urine pH after DOC injection may suggest that older calves compared with the ones at the age of 2-5 weeks have their kidney mechanism regulating potassium and acid-basic balance developed and efficient. Significant effect of hypophysin and desoxycorticosterone acetate on the process of calcium, magnesium and inorganic phosphorus excretion with the urine has not been stated.