FETOPLACENTAL GROWTH AND PLACENTAL PROTEIN-SYNTHESIS IN RATS AFTER CHRONIC MATERNAL COCAINE ADMINISTRATION

This study evaluated the effects of chronic exposure to cocaine during pregnancy on the morphology and function of the placenta. Pregnant ra ts received either 45 or 60 mg/kg of cocaine hydrochloride by i.p. inj ection as a divided daily dose on days 8 to 18 of gestation. The mater nal weight gain decreased by 20% to 24% (P <.05) in the two cocaine tr eatment groups, whereas the placental weight was not significantly alt ered. Fetal growth showed a dose-related decrease in the 45- and 60-mg /kg cocaine treatment groups; fetal body weights and length were signi ficantly decreased by 5% to 10%. The plasma levels of cocaine were 0.7 9 and 1.09 mu g/ml in the 45-and 60-mg treatment dose groups, respecti vely; the level in the fetal plasma was 3-fold higher in the latter gr oup. Placental tissue explants were cultured in the presence of [S-35] -methionine to investigate whether cocaine exposure altered placental protein synthesis. Secreted proteins were analyzed by polyacrylamide g el electrophoresis followed by fluorography or by western blotting and immunostaining with antibodies to placental prolactin-like proteins-B and -C and growth hormone-related protein-1. The data showed that the re were no quantitative or qualitative changes in placental peptide ho rmone secretion as a result of the cocaine treatment. These data indic ate that chronic cocaine exposure in the pregnant rat is associated wi th fetal growth retardation in the absence of alterations in placental morphology or secretory protein synthesis.