| Developmental Exposure of Rats to Chlorpyrifos Elicits Sex-Selective Hyperlipidemia and Hyperinsulinemia in Adulthood Theodore A. Slotkin,1 Kathleen K. Brown,2 and Frederic J. Seidler1 1Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA; 2GlaxoSmithKline Inc., Research Triangle Park, North Carolina, USA Abstract
Developmental exposure to chlorpyrifos alters cell signaling both in the brain and in peripheral tissues, affecting the responses to a variety of neurotransmitters and hormones. We administered 1 mg/kg/day chlorpyrifos to rats on postnatal days 1-4, a regimen below the threshold for systemic toxicity. When tested in adulthood, chlorpyrifos-exposed animals displayed elevations in plasma cholesterol and triglycerides, without underlying alterations in nonesterified free fatty acids and glycerol. This effect was restricted to males. Similarly, in the postprandial state, male rats showed hyperinsulinemia in the face of normal circulating glucose levels but demonstrated appropriate reduction of circulating insulin concentrations after fasting. These outcomes and sex selectivity resemble earlier findings at the cellular level, which identified hepatic hyperresponsiveness to gluconeogenic inputs from β-adrenoceptors or glucagon receptors. Our results thus indicate that apparently subtoxic neonatal chlorpyrifos exposure, devoid of effects on viability or growth but within the parameters of human fetal or neonatal exposures, produce a metabolic pattern for plasma lipids and insulin that resembles the major adult risk factors for atherosclerosis and type 2 diabetes mellitus. Key words: Barker hypothesis, chlorpyrifos, cholesterol, diabetes mellitus type 2, insulin, organophosphates, triglycerides. Environ Health Perspect 113: 1291-1294 (2005) . doi:10.1289/ehp.8133 available via http://dx.doi.org/ [Online 2 June 2005]
Address correspondence T.A. Slotkin, Box 3813 DUMC, Duke University Medical Center, Durham, NC 27710 USA. Telephone: (919) 681-8015. Fax: (919) 684-8197. E-mail: t.slotkin@duke.edu This work was supported by National Institutes of Health grants ES10387 and ES10356. The authors declare they have no competing financial interests. Received 21 March 2005 ; accepted 2 June 2005.
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