This study investigated the effect of food or water deprivation on the pharmacokinetics of paracetamol in 30 Holstein-Friesian preruminant calves (10 controls, 10 food withheld and 10 water-deprived) aged 24-25 days. Control calves were given paracetamol at 24-25 days and again at 28-29 days of age. In the food withheld and water-deprived calves paracetamol studies were performed before and after 4 days of food or water deprivation. In the control group there were no significant differences in pharmacokinetic parameters for paracetamol in 24-25 and 28-29-day-old calves. Witholding food for 4 days was associated with an increase in the mean residence time (MRT) of paracetamol (P < 0.01). When food was withheld total body clearance (ClB) of paracetamol was significantly decreased (P < 0.05). The volume of distribution (Vss) was not significantly altered. Similarly, water deprivation was associated with a significant increase in MRT and significant decrease in ClB of paracetamol (P < 0.01). The Vss was not significantly altered. Food or water deprivation also influenced the formation of major metabolites (glucuronide and sulphate) of paracetamol. It is concluded that food or water deprivation may impair the elimination drugs that undergo metabolism by UDP-glucuronyltransferase and sulphotransferase in cattle.

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The aim of this study was to determine the effect of sex on the metabolism of antipyrine by measuring the antipyrine plasma clearance as well as excretion of three major metabolites in urine in cattle of different ages. The experiment was carried out on 10 female and 10 male cattle of Black and White breed. The antipyrine test was carried out at 1, 2, 4, 6, 8, 12 and 18 months of age for each animal (single dose of 10 mg/kg antipyrine were given intravenously). The concentrations of antipyrine, 4-hydroxyantipyrine (4-OHA), 3-hydroxymethylantipyrine (HMA) and norantipyrine (NORA) were measured in plasma and urine by high performance liquid chromatography (HPLC). The apparent volume of distribution of antipyrine (aVd) decreased significantly between 1 and 18 months of age, but mean aVd values observed in males and females were not statistically different. The experimental period was characterised by a steady decrease (statistically significant) in antipyrine half-life (t1/2beta). These values did not differ significantly between males and females under 12 months. In 12 and 18 month-old animals the antipyrine half-life in the females was significantly shorter than in the males. The systemic clearance (Cls) of antipyrine increased significantly between 1 and 18 months of age. No significant differences were observed between systemic clearance of antipyrine in males and females under 12 months. In 12 and 18 month-old animals the Cls values were significantly higher in females than in males. Following intravenous administration, recovery of antipyrine and its three main metabolites increased significantly with age. These values did not differ significantly between males and females under 12 month of age. In 12 and 18 month-old females the excretion of 4-OHA and HMA in urine was significantly higher than in males at the same age. The excretion of NORA and unchanged antipyrine in males and females did not differ significantly. The partial clearances of antipyrine metabolites (Cl(m)) increased significantly between 1 and 18 months of age. No significant differences were observed between Cl(m) values in males and females under 12 months of age. In 12 and 18 month-old females the partial clearances of 4-OHA and HMA were significantly higher than in males. The clearance of NORA was significantly higher in 18 month-old females than in males. In conclusion, we report a sex-linked difference in plasma antipyrine clearance and urinary excretion of the main metabolites of antipyrine in cattle over 12 months of age, the females being the more active metabolizers.

Investigation of the causes underlying incisor overgrowth in the chinchilla using plasma concentrations of selected minerals. Folia biol. (Kraków) #&: 107-111. The aim of the study was to identify the causes underlying overgrowth of incisors in chinchillas through an analysis of selected plasma electrolyte concentrations, with particular consideration of minerals involved in the formation of osseous tissue, i.e. Ca, Mg, and P. The analysis involved 40 female standard chinchillas managed in a commercial farm system, aged 2 to 4 years, divided into two groups of 20 individuals each: D chinchillas with incisor overgrowth and C controls with normal dentition. Concentrations of Ca, Mg, and P were measured in blood plasma. The analysis was carried out using ICP OES (inductively coupled plasma optical emission spectrometry) by means of the Optima 2000 DV instrument (Perkin Elmer). The resulting data were analysed statistically using one-way ANOVA with Duncans range test. The results show that abnormal metabolism of dental tissue minerals, especially Ca and P, cannot be excluded as the cause of tooth overgrowth in chinchilla.