Chronobiology as it relates to toxicology, pharmacology, and chemotherapy

Examples of circadian (daily) rhythms in man are presented and discussed. This is followed by presentation of experimental data indicating how the temporal organization affects the response of the host to potentially toxic agents, namely amphetamine and sodium pentobarbital. Data also are presented indicating that one unequivocally can improve therapeutic efficacy using the L1210 mouse leukemia model. This was accomplished by taking into consideration the circadian host toxicity response to anticancer agents, namely cytosine arabinoside, adriamycin, and cyclophosphamide. The subject monitored was the "cure rate" subsequent to treatment of different tumor loads.