Accession Number:

AD0662222

Title:

INFLUENCE OF AGE AT EXPOSURE ON SOME PERSISTENT AND LATE EFFECTS OF IRRADIATION WITH FAST NEUTRONS,

Descriptive Note:

Corporate Author:

NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF

Report Date:

1967-10-02

Pagination or Media Count:

32.0

Abstract:

In a duration-of-life study, male Sprague-Dawley rats were exposed to 220 rads of fast neutrons as juveniles 1 month of age, young adults 3 months, middle-aged adults 10, 15 months or as old adults 21 months and compared with their sham-irradiated littermates at intervals using a variety of criteria of radiation injury. In all 5 age groups, there was a deficit in body weight that persisted throughout life. The magnitude of this deficit was inversely related to age at exposure. Decreased food and water consumption were seen throughout life in the group irradiated as juveniles, and were less affected after exposure at older ages. These consummatory changes appeared related to the changes in body size. An age-associated marked increase in water consumption per unit metabolic size occurred earlier than in controls in animals exposed as juveniles or as young adults, but not in the groups exposed at older ages. Proportions of exposed groups with one or more palpable growths were in excess of the proportion for the appropriate controls after exposure at all except the oldest age, in spite of significant life-shortening after exposure at all except the oldest age, in spite of significant life-shortening after exposure at the three younger ages. Proportions of irradiated groups with palpable growths of large size 2.5 cm or more exceeded those for controls even for the group exposed at 21 months. Thus, for criteria of metabolic injury and of the chronologic advancement of degenerative and neoplastic changes, it appears that exposure at a juvenile age is most effective for most criteria, but that some late effects of irradiation are discernible even after exposure during old age. Author

Subject Categories:

  • Radiobiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE