Distribution and effects of intravenous lead in the fetoplacental unit of the rat
Lead metabolism was studied in the fetoplacental unit (FPU) of Wistar rats during the genesis of developmental abnormalities and embryonic death. Female rats were injected iv with tracer /sup 210/Pb(NO/sub 3/)/sub 2/, alone or in combination with 5 or 25 mg Pb(NO/sub 3/)/sub 2//kg, at 9 or 15 days of gestation (dg). The distribution of lead and its effects were determined in the FPUs during the ensuing 30-h period and at 20 dg. Hemorrhage of the egg cylinder was noted as early as 6 h postinjection of 25 mg/kg at 9 dg. By 20 dg, fetuses exhibited characteristic stunting and external malformations (gastroschisis and severe skeletal defects). Administration of this dose at 15 dg produced petechial hemorrhage in fetal brain within 90 min; more massive hemorrhage was a consistent observation by 24 h. At 20 dg, embryo mortality was 44% in rats injected with 25 mg/kg at 9 dg and 100% in those injected at 15 dg. At 90 min after injection, lead content of 15-dg FPUs were 16 times greater. Values remained relatively constant in 15-dg FPUs for 30 h, but early clearance was observed after injection at 9 dg, with a return to 90-min values by 20 dg. In the 15-dg FPUs, placental clearance was followed by fetal lead incorporation, which reached a maximum at 6 h. Fetal lead values were constant from 6 to 30 h after injection at tracer and 5-mg/kg dose levels, but values increased progressively at 25 mg/kg. Both temporal and quantitative relationships of fetal lead metabolism were disrupted by the 25-mg/kg dose, but the nature of the effect was determined by the stage of fetal development at exposure.
- Research Organization:
- Pacific Northwest Lab., Richland, WA
- OSTI ID:
- 5018781
- Journal Information:
- J. Toxicol. Environ. Health; (United States), Vol. 9:5-6
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of dose level and pregnancy on the distribution and toxicity of intravenous lead in rats
Effect of dose level and pregnancy on the distribution and toxicity of intravenous lead in rats
Related Subjects
BRAIN
HEMORRHAGE
LEAD
BIOLOGICAL EFFECTS
TISSUE DISTRIBUTION
SKELETON
MALFORMATIONS
FETUSES
INTRAVENOUS INJECTION
LABELLED COMPOUNDS
LEAD 210
MORTALITY
PLACENTA
RATS
ALPHA DECAY RADIOISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CENTRAL NERVOUS SYSTEM
DISTRIBUTION
ELEMENTS
EVEN-EVEN NUCLEI
FETAL MEMBRANES
HEAVY NUCLEI
INJECTION
INTAKE
ISOTOPES
LEAD ISOTOPES
MAMMALS
MEMBRANES
METALS
NERVOUS SYSTEM
NUCLEI
ORGANS
PATHOLOGICAL CHANGES
RADIOISOTOPES
RODENTS
SYMPTOMS
VERTEBRATES
YEARS LIVING RADIOISOTOPES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)