Tritium effects on germ cells and fertility
Primordial oocytes in juvenile mice show acute gamma-ray LD/sub 50/ as low as 6 rad. This provides opportunities for determining dose-response relations at low doses and chronic exposure in the intact animal - conditions of particular interest for hazard evaluation. Examined in this way, /sup 3/HOH in body water is found to kill murine oocytes exponentially with dose, the LD/sub 50/ level for chronic exposure being only 2..mu..Ci/ml (delivering 0.4 rad/day). At very low doses and dose rates, where comparisons between tritium and other radiations are of special significance for radiological protection, the RBE of tritium compared with /sup 60/Co gamma radiation reaches approximately 3. Effects on murine fertility from tritium-induced oocyte loss have been quantified by reproductive capacity measurements. Chronic low-level exposure has been examined also in three primate species - squirrel, rhesus, and bonnet monkeys. In squirrel monkeys the ovarian germ-cell supply is 99% destroyed by the time of birth from prenatal exposure to body-water levels of /sup 3/HOH (administered in maternal drinking water) of only 3 ..mu..Ci/ml, the LD/sub 50/ level being 0.5 ..mu..Ci/ml (giving 0.1 rad/day), one fourth that in mice. Though not completely ruled out, similar high sensitivity of female germ cells has not been found in macaques; and it probably does not occur in man. The exquisite radiosensitivity of primordial oocytes in mice is apparently due to vulnerability of the plasma membrane (or something of similar geometry and location), not DNA. Evidence for this comes from tritium data as well as neutron studies. Tritium administered as /sup 3/HOH, and therefore generally distributed, is much more effective in killing murine oocytes than is tritium administered as /sup 3/H-TdR, localized in the nucleus. This situation in the mouse may have implications for estimating radiation genetic risk in the human female.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6514414
- Report Number(s):
- UCRL-88376; CONF-821167-1; ON: DE83007349
- Resource Relation:
- Conference: European seminar on the risks from tritium exposure, Mole, Belgium, 22 Nov 1982
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
OOCYTES
RADIOSENSITIVITY
TRITIUM
BIOLOGICAL RADIATION EFFECTS
CHRONIC EXPOSURE
DOSE-RESPONSE RELATIONSHIPS
DRINKING WATER
EXPERIMENTAL DATA
INGESTION
LETHAL RADIATION DOSE
LOW DOSE IRRADIATION
MICE
MONKEYS
RBE
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
DATA
DOSES
GERM CELLS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
INTAKE
IRRADIATION
ISOTOPES
LETHAL DOSES
LIGHT NUCLEI
MAMMALS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
PRIMATES
RADIATION DOSES
RADIATION EFFECTS
RADIOISOTOPES
RODENTS
VERTEBRATES
WATER
YEARS LIVING RADIOISOTOPES
560162* - Radionuclide Effects
Kinetics
& Toxicology- Animals
Plants
Microorganisms
& Cells