Behavioral teratology of ethylene glycol monomethyl and monoethyl ethers

A recent addition to the field of teratology has been the inclusion of functional assessment techniques of offspring after prenatal exposure to exogenous agents. The present paper reviews the behavioral teratogenic effects of ethylene glycol monomethyl ether (EGME, 2-methoxyethanol) and ethylene glycol monoethyl ether (EGEE, 2-ethoxyethanol). Groups of 15 pregnant Sprague-Dawley rats were exposed via inhalation to 25 ppm EGME or to 100 ppm EGEE on gestation days 7 to 13 or 14 to 20. An equal number of sham-exposed controls were included for both periods of gestation. The only effect noted in the maternal animals was a slightly prolonged gestation in the group exposed to 100 ppm EGEE on days 14 to 20. Litters were culled to four female and four male pups on the day of birth. Pups of each sex from all litters were tested on a variety of behavioral tasks (including tests of neuromuscular ability, activity, and learning ability) extending from postnatal days 10 to 90. In addition, brains from newborn and from 21-day-old offspring were removed and analyzed for concentrations of the neurotransmitters acetylcholine, dopamine, norepinephrine, and 5-hydroxytryptamine (serotonin). Both the behavioral testing and the neurochemical evaluations revealed functional alterations in the litter groups experiencing prenatal exposure to EGME and EGEE at concentrations which produced no observable effects in the maternal animals.