EFFECTS OF LOW-LEVEL PRENATAL CO-60 GAMMA-IRRADIATION ON POSTNATAL-GROWTH AND BEHAVIOR IN MICE

Pregnant Kun Ming strain mice were exposed to a total dose of 0, 0.1, 0.2, or 0.4 Gy from Co-60 gamma-rays from the 13th to the 18th days of gestation. An overall delay of the appearance of two physiologic mark ers (pinna detachment, eye opening) and the age of acquisition of four reflexes (surface righting, air righting, auditory startle, visual pl acing) was observed in offspring exposed to 0.2 or 0.4 Gy in utero. Po stnatal growth retardation, shortened length of hanging time, inhibite d exploratory activity in the hole board test (decreased number of hea d-dipping), and hyperactivity in the open field test (shortened latenc y to leave the center area and increased number of squares entered) we re also found among the offspring exposed to 0.2 Gy or more in utero. The results indicate that 0.1-0.2 Gy may represent a threshold range i n mice for certain physiologic and behavioral effects resulting from c ontinuous exposure to Co-60 gamma-rays on the 13th-18th days of gestat ion. (C) 1993 Wiley-Liss, Inc.