Altered distribution and toxicity of digitoxigenin in fasted mice.
Intravenous administration of digitoxigenin (DTXGN) evokes seizure episodes in mice which may be dependent on brain biogenic amines such as serotonin (5-HT). Fasting is known to have effects on both drug toxicity and brain 5-HT synthesis. The purpose of this study was to assess the effects of overnight fasting on DTXGN toxicity. The i.v. LD-50 of DTXGN was increased by 61% in fasted mice. Adjustment of DTXGN dose for the decrease in body weight of fasted mice did not alter the fasting induced protection. A loading dose of 1-tryptophan (25 mg/kg, i.p.) did not alter mortality rates in either fed or fasted mice. Cortical levels of 3H-DTXGN were decreased significantly by 25% in fasted mice. Liver and blood levels were elevated significantly. These data suggest that decreased DTXGN toxicity is associated with a decrease in its distribution to the cerebral cortex and emphasize the importance of acute dietary status in the expression of drug toxicity.