THE BASIC MOLECULAR-BIOLOGY UNDERLYING RADIATION HORMESIS

Despite satisfactory explanations of all major effects, from a variation in the cancer rate due to background radiation to the time function of radiation induced cancer after Hiroshima and Nagasaki and the associated additive or multiplicative radiation risk found by the Random Coincidence Model (RCM), some major questions about the mechanisms of hormesis have remained open to this day. They are discussed in this article, and solutions are proposed. The key question is that of the stimulation of the repair system by radiation. What does this principle imply, and how does it work? Why is radiation a stronger stimulant of the repair system than chemical lesions with their damage rates higher by many orders of magnitude? What causes the drastic reduction in the defect rate in DNA after pre-irradiation? Is there any explanation of this ''better'' repair other than faster repair (RCM)? What happens in RCM with multiple base defects, double strand breaks and DNA protein cross-links caused by radiation.