Comparison of the effects of radiation and hyperthermia on prenatal retardation of brain growth of guinea-pigs.
On day 21 of pregnancy guinea-pigs were exposed to hyperthermia or gamma radiation. The effects on prenatal growth and especially brain growth of offspring were compared. Doses of 0.04-0.99 Gy of radiation produced a dose-dependent and irreversible reduction of brain weight in the offspring, but had little effect on body weight. Treatment with hyperthermia resulting in maternal temperatures of 41.8-43.9 degrees C after exposure in a heated incubator for an hour also produced a dose-related micrencephaly in the offspring. Comparison of the two agents showed that a dose increment of 0.525 Gy of radiation produced a deficit in brain weight equivalent to an elevation of 1 degree C in maternal temperature. Using this guinea-pig brain weight assay system a threshold was detected of between 0.05 and 0.10 Gy for retardation of brain growth.
D000016:Abnormalities, Radiation-Induced / Q000209:etiology*; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000528:radiation effects; D001921:Brain / Q000196:embryology / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D006168:Guinea Pigs; D006358:Hot Temperature / Q000009:adverse effects*; D008297:Male; D008831:Microcephaly / Q000209:etiology*; D009929:Organ Size / Q000528:radiation effects; D011247:Pregnancy