ABSTRACT

In mammals, ornithine decarboxylase (ODC) activity is highest during periods of rapid cellular growth and development, and the normal pattern of ODC activity during this period is sensitive to chemical and drug exposure. The industrial solvent ethylene glycol monomethyl ether (EGME) is teratogenic to rats and mice, with the heart being particularly sensitive. Basal ODC activity and ODC activity following an isoproterenol challenge were used to assess heart function in 3-, 9-, 16- and 22- day-old offspring from dams treated with 25 mg/kg EGME by gavage on days 7–13 or 13–19 of gestation. Reproductive outcome was not affected by EGME and none of the offspring had gross physical abnormalities. Gestation length was prolonged by both EGME treatments, but the increase was statistically significant only in the group treated on days 7–13 gestation. ODC activity per mg protein was greatest in 3-day-old rats and dropped off sharply during the following 3 weeks. In 3-day-old rats exposed on days 7–13 of gestation, ODC activity was 54% of that found in controls. ODC activity was comparable to that in controls in 3-day-old rats exposed on days 13–19 of gestation. Isoproterenol increased ODC activity in all groups, but additional functional abnormalities were not revealed by the isoproterenol challenge.