AMINOPYRINE INFUSION BREATH TEST FOR THE DETERMINATION OF CHANGES IN P450 METABOLISM IN-VIVO

1. An osmotic mini-pump was used to maintain a constant infusion of ra diolabelled [N-dimethyl-C-14] aminopyrine into a rat. After implanting the mini-pump, (CO2)-C-14 expiration rate was constant within 12 h, a nd this rate was maintained for 192 h. 2. Treatment with 2-diethylamin oethyl-2,2-diphenylvalerate HCl (SKF 525-A) or cimetidine, inhibitors of P450-dependent metabolism, resulted in both dose- and time-dependen t inhibition of the expiration of (CO2)-C-14.