title: A circadian susceptibility/resistance rhythm for potassium cyanide in male BALB/cCr mice.
abstract: Circadian rhythms in mortality and/or survival time following a single intraperitoneal injection of a LD50 of potassium cyanide were studied. In two investigations, different but comparable subgroups of inbred male BALB/cCr mice were treated at 4-h intervals (under conditions standardized for chronobiologic study) during 24-h spans. Mice were observed for exact time-to-death during the first hour after treatment as well as overall mortality during the entire 24-h post-injection span following each KCN treatment timepoint. In both studies, mortality from KCN exhibited a 24-h rhythm. Highest mortality occurred in mice injected at 1600 (80% mortality) in Experiment 1 and 2000 (100% mortality) in Experiment II. Lowest mortality occurred at 0400 (40% mortality) in Experiment I and 0800 (30% mortality) in Experiment II. The need to consider the circadian organization of physiologic function when bioassaying toxicity is discussed.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D003486:Cyanides / Q000633:toxicity*; D004351:Drug Resistance; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011190:Potassium Cyanide / Q000633:toxicity*; D013997:Time Factors
chemical_list: D003486:Cyanides; D011190:Potassium Cyanide