THE ACTIVITY OF MIXED-FUNCTION OXIDASES, ESTIMATED BY IN-VIVO ANTIPYRINE CLEARANCE, IS SIMILAR IN HORSES AND CAMELS

The activity of hepatic mixed function oxidases was compared in horses and camels (Camelus dromedarius) by studying the pharmacokinetics of antipyrine in seven camels and five horses following intravenous admin istration of a single dose of antipyrine (25 mg/kg). The data obtained (mean +/- SEM and median in brackets) in camels and horses, respectiv ely, were as follows: the elimination half-lives were 3.25 +/- 0.23 (3 .19) and 3.09 +/- 0.25 (2.90) hr; the apparent volumes of distribution (area method) were 0.691 +/- 0.0 45 (0.648) and 0.642 +/- 0.0 34 (0.6 76) 1/kg; the volumes of distribution at steady state were 0.659 +/- 0 .0 40 (0.607) and 0.620 +/- 0.0 30 (0.653) l/kg; the volume of the cen tral compartment of the two compartment pharmacokinetic model were 0.3 86 +/- 0.0523 (0.349) and 0.298 +/- 0.05 (0.308) l/kg; total body clea rances were 0.148 +/- 0.008 (0.158) and 0.145 +/- 0.007 (0.147) l/kg/h r; the areas under the curves to infinity were 171.0 +/- 9 (165) and 1 75 +/- 8.0 (170) mu g. mi. hr. There was no statistical significance i n any parameter between camels and horses which suggests that the acti vity of hepatic mixed function oxidases is similar in horses and camel s. (C) 1998 Elsevier Science Inc.