A Review of Certain Low-level Ionizing Radiation Studies in Mice and Guinea Pigs
- 1 May 1987
- journal article
- review article
- Published by Wolters Kluwer Health in Health Physics
- Vol. 52 (5) , 593-597
- https://doi.org/10.1097/00004032-198705000-00010
Abstract
Starting in the early 1940s, Egon Lorenz and collaborators at the National Cancer Institute began an extended study of chronic low-level ionizing radiation effects in what was then the tolerance range for man. Observations on life span, body weight and radiation carcinogenesis, among others, were made in mice, guinea pigs and rabbits. At the then-permissible exposure level, 0.1 R** per 8-h day until natural death, experimental mice and guinea pigs had a slightly greater mean life span compared to control animals. In addition, there was marked weight gain during the growth phase in both species. Increased tumor incidence was also observed at the 0.1-R level in mice. The primary hypothesis for increased median life span has been rebound regenerative hyperplasia during the early part of the exposure; in the presence of continuing injury, there is physiological enhancement of defense mechanisms against intercurrent infection. The body weight gain has not been explained.Keywords
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