The influence of age on the gastrointestinal absorption of mercuric chloride and methyl mercury chloride in the rat
The intestinal absorption of mercuric chloride and methyl mercury chloride was determined in neonatal (6-day-old) and mature (7-week-old) rats. No differences between the two age groups were observed in the absorption of methyl mercury chloride (0.08 ..mu..g Hg/ml) determined up to 2 hr after administration in vivo into closed segments of the duodenum or ileum. In contrast, the 1-hr duodenal absorption of mercuric chloride (8 ..mu..g Hg/ml) was significantly greater in neonatal animals (18.1%) as compared to 23-day-old weanling (7.3%) or mature (3.6%) animals. Ileal absorption of mercuric chloride was also higher in neonates than in mature animals, but the magnitude of the differences was less than that observed in the duodenum. GI absorption of mercuric chloride (46 ..mu..g Hg/kg) was also assessed in neonatal, weanling, and mature rats at 4 and 43 hr after gastric intubation. The percentage of the dose in the carcass, determined after removal of the GI tract, was significantly higher at both times in neonatal and weanling rats as compared to mature animals. Analysis of mercury content in the gastrointestinal tract of these animals also indicated age-dependent differences in mercury transit through the GI lumen. The extent of gastric emptying of mercury by 4 hr after dosing was significantly less in neonatal and weanling rats compared to mature animals. In addition, the small intestinal transit of mercury was markedly slower in neonates with 74.8% of the dose in the GI tract after 43 hr as compared to 5.2% and 3.0% in weanling and mature animals, respectively. These findings indicate that in the neonate, exposure to inorganic mercury by the oral route can be expected to result in higher systemic, as well as small intestinal, levels of mercury because of enhanced GI absorption and decreased luminal transit, resepectively.
- Research Organization:
- Boston Univ. Medical Center, MA
- OSTI ID:
- 5528124
- Journal Information:
- Environ. Res.; (United States), Journal Name: Environ. Res.; (United States) Vol. 27:2; ISSN ENVRA
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ABSORPTION
AGE DEPENDENCE
ANIMALS
BIOLOGICAL EFFECTS
CHLORIDES
CHLORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INTESTINAL ABSORPTION
MAMMALS
MERCURY CHLORIDES
MERCURY COMPOUNDS
MERCURY HALIDES
METHYLMERCURY
ORGANIC COMPOUNDS
ORGANIC MERCURY COMPOUNDS
RATS
RODENTS
UPTAKE
VERTEBRATES