Light-mediated perturbations of circadian timing and cancer risk: a mechanistic analysis.

In industrialized countries, certain types of cancer, most notably, breast and prostate, are more frequent than in poorly developed nations. This high cancer frequency is not explained by any of the conventional causes. Within the past decade, numerous reports have appeared that link light at night with an elevated cancer risk.

The circadian melatonin rhythm and its modulation: possible impact on hypertension.

In experimental rodents, surgical removal of the pineal gland, the major source of circulating melatonin, causes a gradual and sustained rise in blood pressure. Conversely, when melatonin is chronically administered to pinealectomized rodents the increment in blood pressure is ameliorated. In humans as well, the night time rise in endogenous circulating melatonin levels may be inversely related to the reduction in night time blood pressure.

Reducing oxidative/nitrosative stress: a newly-discovered genre for melatonin.

The discovery of melatonin and its derivatives as antioxidants has stimulated a very large number of studies which have, virtually uniformly, documented the ability of these molecules to detoxify harmful reactants and reduce molecular damage. These observations have clear clinical implications given that numerous age-related diseases in humans have an important free radical component. Moreover, a major theory to explain the processes of aging invokes radicals and their derivatives as causative agents.