title: Characterization of o,p'-DDT-stimulated contraction frequency in rat uterus in vitro.
abstract: Exposure to organochlorine pesticides, including DDT, has previously been associated with premature birth. Using an improved protocol to characterize dose and time dependent responses, the present report extends a preliminary finding by this laboratory that o,p'-DDT directly stimulates uterine contractility. Contraction frequency was determined in longitudinal uterine strips from pregnant rats under isometric force conditions. Following equilibration, the uterine strips were monitored for a 1-hr baseline period, then treated with o,p'-DDT or ethanol (solvent control) for 3 hr, followed by 3 hr without test substance. During exposure to 100 microM o,p'-DDT, the frequency of contraction significantly increased by 66% relative to matched controls. After removal of o,p'-DDT from the medium, the frequency of contraction continued to increase in uterine strips exposed to 50 and 100 microM o,p'-DDT. A dose effect was clearly observed during the post-treatment period, with 50 and 100 microM o,p'-DDT significantly increasing contraction frequency by 39 and 104% relative to controls. No significant differences in contraction frequency were observed with 10 microM o,p'-DDT during any test period. These data show that o,p'-DDT directly stimulated isometric contractions in rat uterine strips.
authors.affiliation: Department of Environmental and Industrial Health, University of Michigan, Ann Arbor 48109-2029.
authors.forename: D R
authors.initials: DR
authors.lastname: Juberg
authors.forename: R C
authors.initials: RC
authors.lastname: Webb
authors.forename: R
authors.initials: R
authors.lastname: Loch-Caruso
mesh_terms: D000818:Animals; D003634:DDT / Q000633:toxicity*; D005260:Female; D066298:In Vitro Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D003634:DDT