Comparative Pharmacokinetics of Ethanol in Inbred Strains of Mice Using Doses Based on Total Body Water

The mean total body water was determined by desiccation in DBA/2J, CBA/J, and C57BL/6J mice to be 60.6, 65.6, and 68.6 percent of body weight, respectively. The pharmacokinetics of ethanol was subsequently studied in mice of these strains given an intraperitoneal dose of 116 mmoles/l of total body water based on the desiccation study. This dose was equivalent to 70, 76, and 80 mmoles/kg in the DBA/2J, CBA/J, and C57BL/6J strains, respectively. The zero time concentrations were nearly identical between strains; therefore volume of distribution (VD) estimates based on mmole/kg doses reflected interstrain differences in total body water. The apparent zero order elimination rate was significantly greater in the DBA/2J strain versus the other two strains using this regimen. Interstrain differences in ethanol sleep time paralleled the differences in anesthetic sensitivity evidenced by blood concentrations at the time of regaining the righting reflex. The results demonstrate the importance of considering differences in total body water and hence ethanol VD when comparing the effects of ethanol in inbred mouse strains.