Some Aspects of Brain Neurochemistry after Intrauterine Exposure to Tritium

Summary

Rats were continuously exposed to tritiated water (0, 1, 10 and 100 µCi HTO/ml body water) from conception to birth. Calculated, cumulative whole-body doses to the embryo and foetus were approximately 0, 6·6, 66 and 660 rad.

The levels of several enzymes and established or presumptive central nervous system neurotransmitters were examined postnatally in whole brains. These were norepinephrine (NE), dopamine (DA), acetylcholinesterase (AChE) and monoamine oxidase (MAO). Intrauterine exposures to doses as low as 66 rad produced measurable and persistent decreases in brain weight and increases in NE concentrations at 21 and 45 days postnatally. No differences from control values were seen in the rate of turnover of NE or the concentrations of DA, AChE or MAO at 45 days. Exposure in utero to 6·6 rad produced no detectable postnatal effects on the brain neurochemical parameters measured.