The weeks shown in color represent the start and end points of chemical exposure for each study.

Study Results Study Details References

Results for Chlorpyrifos

Decreased body weight in adutlhood at 1 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0, 2.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational day 21 and post-natal day 60

Reference [PubMed Link]
Meyer A, Seidler FJ, Slotkin TA. 2004. Developmental effects of chlorpyrifos extend beyond neurotoxicity: critical periods for immediate and delayed-onset effects on cardiac and hepatic cell signaling. Environ Health Perspect 112(2):170-178.
Study Results Study Details References

Results for Chlorpyrifos

Decreased heart weight in adulthood at 1 mg/kg; increased Beta-adrenergic receptor binding in the heart at gestational day 21 at 1 and 2 mg/kg; increased adenylyl cyclase basal activity in the heart at gestational day 21 at 1 and 2 mg/kg; decreased adenylyl cyclase activity stimulated by isoproterenol in the heart at gestational day 21 at 5 mg/kg; increased adenyly cyclase activity stimulated by Mn2+ in the heart at gestational day 21 at all doses; increased total induced activity of adenylyl cyclase in the heart of males at post-natal day 60 at 1 mg/kg

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0, 2.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational day 21 and post-natal day 60

Reference [PubMed Link]
Meyer A, Seidler FJ, Slotkin TA. 2004. Developmental effects of chlorpyrifos extend beyond neurotoxicity: critical periods for immediate and delayed-onset effects on cardiac and hepatic cell signaling. Environ Health Perspect 112(2):170-178.
Study Results Study Details References

Results for Chlorpyrifos

Increased DNA content; increased m2-AChRs at 1 mg/kg at gestational day 21; decreased m2-AChRs at 5 mg/kg at gestational day 21

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0, 2.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational days 17 and 21

Reference [PubMed Link]
Qiao D, Seidler FJ, Padilla S, Slotkin TA. 2002. Developmental neurotoxicity of chlorpyrifos: What is the vulnerable period? Environ Health Perspect 110(11):1097-1103.
Study Results Study Details References

Results for Chlorpyrifos

Increased DNA content measured at gestational day 17; decreased DNA content at gestational day 21; decreased protein/DNA ratio at 2 and 5 mg/kg measured at gestational day 17; increased protein/DNA ratio at 2 and 5 mg/kg at gestational day 21

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0, 2.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: gestational days 17 and 21

Reference [PubMed Link]
Qiao D, Seidler FJ, Padilla S, Slotkin TA. 2002. Developmental neurotoxicity of chlorpyrifos: What is the vulnerable period? Environ Health Perspect 110(11):1097-1103.
Study Results Study Details References

Results for Chlorpyrifos

Decreased body weight of females across adolescence and adulthood

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: post-natal day 30 and 60

Reference [PubMed Link]
Qiao D, Seidler FJ, Abreu-Villaca Y, Tate CA, Cousins MM, Slotkin TA. 2004. Chlorpyrifos exposure during neurulation: cholinergic synaptic dysfunction and cellular alterations in brain regions at adolescence and adulthood. Developmental Brain Research 148(1):43-52.
Study Results Study Details References

Results for Chlorpyrifos

Increased incidence of dismorphogenesis at 5 μg/ml

Subjects: Sprague-Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 0.5 or 5 μg/ml

Other doses tested: 50 μg/ml

Route of administration: dissolved in media with DMSO in vitro

Exposure duration: gestational day 9.5 – gestational day 11.5 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 4)

Age of measurement: gestational day 11.5

Reference [PubMed Link]
Roy TS, Andrews JE, Seidler FJ, Slotkin TA. 1998. Chlorpyrifos elicits mitotic abnormalities and apoptosis in neuroepithelium of cultured rat embryos. Teratology 58(2):62-68.
Study Results Study Details References

Results for Chlorpyrifos

Increased norepinephrine levels at 1.0 and 5.0 mg/kg treatment levels

Subjects: Sprague Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: post-natal day 30

Reference [PubMed Link]
Seidler FJ, Slotkin TA. 2011. Developmental neurotoxicity targeting hepatic and cardiac sympathetic innervation: effects of organophosphates are distinct from those of glucocorticoids. Brain Res Bull 85(3-4):225-230.
Study Results Study Details References

Results for Chlorpyrifos

Increased norepinephrine levels at 1.0 and 5.0 mg/kg treatment levels

Subjects: Sprague Dawley rats

Chemical: Chlorpyrifos

Low doses tested: 1.0 or 5.0 mg/kg bw/d

Route of administration: dissolved in DMSO and injected subcutaneously

Exposure duration: gestational day 9 – gestational day 12 (comparable to human prenatal development from approximately day 1 of week 3 to day 1 of week 5)

Age of measurement: post-natal day 30

Reference [PubMed Link]
Seidler FJ, Slotkin TA. 2011. Developmental neurotoxicity targeting hepatic and cardiac sympathetic innervation: effects of organophosphates are distinct from those of glucocorticoids. Brain Res Bull 85(3-4):225-230.