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Risk assessments and chronobiology
REGULATORY
TOXICOLOGY
AND
PHARMACOLOGY
15,225
(1992)
EDITORIAL Risk Assessments
and Chronobiology
In this issue attention is directed to a little publicized development in the biomedical sciences in recent years. Very gently the new fields of chronopharmacology, chronodynamics, chronopharmacokinetics, and chronotoxicology have become of scientific interest. Various aspects of cellular circadian rhythms as related to cell susceptibility to injury or resistance from chemicals or drugs have been shown to play a significant role in pharmacology and toxicology. Biological rhythms are now replacing or modifying the traditional unidimensional reference intervals of timing of exposure to drugs or potentially hazardous substances. Convincing demonstrations show that the unique hormonal product melatonin plays a major role as a photoperiodic signal for virtually every organ system of the body in all vertebrates, including human beings. In addition to the light-dark sequence of our lives it appears that now we should consider other forms of electromagnetic energy since both modify the circadian basis of melatonin. Chronobiological modifications have proved to increase or decrease therapeutic drug effectiveness and modify toxicity. A cluster of diseases has been treated successfully by utilizing the indwelling biological rhythm’s influence on diagnosis and therapy. These clinical reports are appearing in the medical literature but the research community has had little use for these biological constructs. It is time to recognize and utilize this knowledge that has profound beneficial influence in our understanding of risks, and for regulatory bodies to act upon these scientific discoveries. It is worth noting that the official journal of the Society of Chronobiology, Chronobiology international, carries papers on basic and applied biological rhythm research and their annual conference this year includes a session on regulatory implications of chronobiology. These agencies should consider appropriate recognition of the scientific basis of the advantages of chronotoxicology and chronopharmacology. The apparent reluctance to utilize these scientific developments is a puzzle and the baffling fact remains that there seems to be antipathy and aversion on the part of research investigators and clinicians to utilize this chronobiological information. The paper in this issue emphasizes that both visible and nonvisible portions of the electromagnetic spectrum influence organ systems which are dependent on the melatonin signal for their normal function. Although animal experiments suggest an oncogenic effect of melatonin, the evidence for an increased incidence of cancer in humans who lack a normal melatonin rhythm is not available. Therefore, this issue remains equivocal in terms of environmental toxicology. C.JELLEFFCARR 225 02?3-2300192 $5.00 Copyright 0 1992 by Academic Press. Inc. All rights of reproduction in any form resa-ved.
TOXICOLOGY
AND
PHARMACOLOGY
15,225
(1992)
EDITORIAL Risk Assessments
and Chronobiology
In this issue attention is directed to a little publicized development in the biomedical sciences in recent years. Very gently the new fields of chronopharmacology, chronodynamics, chronopharmacokinetics, and chronotoxicology have become of scientific interest. Various aspects of cellular circadian rhythms as related to cell susceptibility to injury or resistance from chemicals or drugs have been shown to play a significant role in pharmacology and toxicology. Biological rhythms are now replacing or modifying the traditional unidimensional reference intervals of timing of exposure to drugs or potentially hazardous substances. Convincing demonstrations show that the unique hormonal product melatonin plays a major role as a photoperiodic signal for virtually every organ system of the body in all vertebrates, including human beings. In addition to the light-dark sequence of our lives it appears that now we should consider other forms of electromagnetic energy since both modify the circadian basis of melatonin. Chronobiological modifications have proved to increase or decrease therapeutic drug effectiveness and modify toxicity. A cluster of diseases has been treated successfully by utilizing the indwelling biological rhythm’s influence on diagnosis and therapy. These clinical reports are appearing in the medical literature but the research community has had little use for these biological constructs. It is time to recognize and utilize this knowledge that has profound beneficial influence in our understanding of risks, and for regulatory bodies to act upon these scientific discoveries. It is worth noting that the official journal of the Society of Chronobiology, Chronobiology international, carries papers on basic and applied biological rhythm research and their annual conference this year includes a session on regulatory implications of chronobiology. These agencies should consider appropriate recognition of the scientific basis of the advantages of chronotoxicology and chronopharmacology. The apparent reluctance to utilize these scientific developments is a puzzle and the baffling fact remains that there seems to be antipathy and aversion on the part of research investigators and clinicians to utilize this chronobiological information. The paper in this issue emphasizes that both visible and nonvisible portions of the electromagnetic spectrum influence organ systems which are dependent on the melatonin signal for their normal function. Although animal experiments suggest an oncogenic effect of melatonin, the evidence for an increased incidence of cancer in humans who lack a normal melatonin rhythm is not available. Therefore, this issue remains equivocal in terms of environmental toxicology. C.JELLEFFCARR 225 02?3-2300192 $5.00 Copyright 0 1992 by Academic Press. Inc. All rights of reproduction in any form resa-ved.