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Long-term effects of prenatal atrazine exposure on physiology, body composition, and stress reactivity in rats
Citation:
GRACE, C. E., C. Aydin, A. F. JOHNSTONE, C. J. GORDON, AND J. M. ROGERS. Long-term effects of prenatal atrazine exposure on physiology, body composition, and stress reactivity in rats. Presented at Ssociety of Toxicology (SOT) Annual Meeting, San Francisco, CA, March 11 - 15, 2012.
Impact/Purpose:
These data indicate that exposure to chemicals that increase maternal CORT levels may lead to similar adult diseases as observed in maternal stress and undernutrition studies.
Description:
Low birth weight in humans is associated with increased risk of coronary heart disease, hypertension, and diabetes in adulthood. Experimental studies have also reported that undernutrition, stress or exposure to glucocorticoids during pregnancy is associated with hypertension, glucose intolerance, obesity, and altered stress reactivity. The mechanism(s) of these effects may be due to increased fetal exposure to maternal glucocorticoids. We hypothesized that environmental contaminants that increase maternal corticosterone (CORT) levels would elicit similar effects in offspring. Atrazine, a widely used herbicide, increases CORT in female rats. We exposed pregnant rats to 125 mg/kg/d atrazine, 0.1 mg/kg/d dexamethasone (DEX), or methyl cellulose vehicle from gestational day 14-20. Offspring were divided into 3 test groups: adult offspring were surgically implanted with radio transmitters for recording blood pressure (BP), core temperature, heart rate (HR), and activity during and without l h restraint for 4 d (group 1); body composition was measured by magnetic resonance (Broker) to determine percent body fat (group 2); and stress reactivity was measured by determining serum CORT levels prior to, during, and following 1h restraint (group 3). Baseline BP was increased in atrazine and DEX-treated animals, but differences were minimal during restraint. HR and temperature decreased daily during restraint, suggesting adaptation, but BP was elevated on subsequent days. Body fat was increased and lean mass decreased in DEX-treated female offspring. Prenatal atrazine treatment altered the adult offspring response to restraint; CORT levels were increased and did not return to control levels 2 h following restraint. These data indicate that exposure to chemicals that increase maternal CORT levels may lead to similar adult diseases as observed in maternal stress and undernutrition studies. Disclaimer: This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.