Influence of short-term water deprivation on antipyrine disposition in calves.

The effect of four days water deprivation on the metabolism of antipyrine was studied in female Holstein-Friesian calves, aged 24 to 25 days, by measuring the antipyrine plasma clearance and the excretion of three major metabolites of antipyrine in urine. Water deprivation was associated with a statistically significant (P < 0.01) increase in the plasma antipyrine elimination half-life from 10.85(1.14) hours to 14.00(1.05) hours. In water deprived calves the systemic clearance of antipyrine was significantly (P < 0.05) decreased from 0.75(0.07) ml min-1 kg-1 to 0.56(0.05) ml min-1 kg-1. The excretion of three major metabolites of antipyrine: 4-hydroxyantipyrine, 3-hydroxymethylantipyrine and norantipyrine in urine was significantly (P < 0.01) decreased after water deprivation. In the control group no significant differences between the pharmacokinetic parameters of antipyrine in 24 to 25 and 28 to 29 day-old calves were observed. Also urinary profiles of antipyrine in calves from the control group did not differ significantly between 24 to 25 and 28 to 29 days of life. Our data indicate that water deprivation inhibits antipyrine elimination in calves.