US EPA

1297859 

Journal Article 

Review 

[Biological responses to low dose radiation--hormesis and adaptive responses] 

Sakai, K 

2006 

1 

Yakugaku Zasshi
ISSN: 0031-6903
EISSN: 1347-5231 

126 

10 

827-831 

jpn 

17016013 

"Hormesis" is defined, originally in the field of toxicology, as a phenomenon in which a harmful substance gives stimulating effects to living organisms when the quantity is small. The concept was extended and applied to ionizing radiation, high doses of which are harmful. Although radiation has been thought to be, based on findings in high dose ranges, harmful no matter low the dose is, recent investigation revealed that living organisms possess the ability to respond to low-dose radiation in very sophisticated ways. A good example of such responses is the so-called radiation adaptive response, a process in which acquired radioresistance is induced by low-dose radiation given in advance. The stimulation of certain bioprotective functions, including antioxidative capacity, DNA repair functions, apoptosis, and immune functions are thought to underly the adaptive response. The adaptive response is effective for chromosome induction, acute death, and tumorigenesis induced by high doses of radiation. Radiation hormesis and adaptive response provide a new scope in the risk assessment and medical application of ionizing radiation.