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.