Uptake and excretion of ( UC)methyl bromide as influenced by exposure concentration

Journal Article · Mon Dec 31 23:00:00 EST 1984 · Toxicol. Appl. Pharmacol.; (United States)

DOI:https://doi.org/10.1016/0041-008X(85)90285-6· OSTI ID:6044297

Medinsky, M A; Dutcher, J S; Bond, J A; Henderson, R F; Mauderly, J L; Snipes, M B; Mewhinney, J A; Cheng, Y S; Birnbaum, L S

Uptake of methyl bromide and pathways for excretion of UC were investigated in male Fischer-344 rats after nose-only inhalation of 50, 300, 5700, or 10,400 nmol (1.6 to 310 ppm) of ( UC)methyl bromide/liter of air for 6 hr. Fractional uptake of methyl bromide decreased at the highest concentrations, 5700 and 10,400 nmol/liter, with 37 and 27% of the inhaled methyl bromide absorbed, respectively, compared to 48% at the lower levels. Total methyl bromide absorbed was 9 or 40 mol/kg body wt after exposure to 50 or 300 nmol/liter, respectively. Elimination of UC was linearly related to the amount of methyl bromide absorbed as determined from urine, feces, expired CO2, and parent compound collected for 66 hr after the end of exposure. Exhaled UCO2 was the dominant route of excretion, with from 1.2 to 110 mol (50% of amount absorbed) exhaled, and was described by a two-component negative exponential function; 85% was exhaled with t1/2 of 4 hr, and the remaining 15% was exhaled with a t1/2 of 17 hr. The rate of exhalation of UCO2 was not affected by the amount of ( UC)methyl bromide absorbed. From 0.4 to 54 mol was excreted in urine (20% of amount absorbed). The half-time for excretion of UC in urine was approximately 10 hr, and the rate of excretion was not dependent on the amount of ( UC)methyl bromide absorbed. Little UC was exhaled as methyl bromide (<4% of the dose) or excreted in feces (<2%). At the end of 66 hr, 25% of the UC absorbed remained in the rats. Liver, kidneys, adrenals, lungs, thymus, and turbinates (maxilloturbinates, ethmoturbinates, and nasal epithelial membrane) contained the highest concentrations of UC. Results indicated that uptake of inhaled methyl bromide could be saturated. Any ( UC)methyl bromide equivalents absorbed, however, would be excreted by concentration-independent mechanisms. 20 references, 5 figures, 4 tables.

• Research Organization: Inhalation Toxicology Research Institute, Albuquerque, NM
• DOE Contract Number: AC04-76EV01013
• OSTI ID: 6044297
• Journal Information: Toxicol. Appl. Pharmacol.; (United States), Journal Name: Toxicol. Appl. Pharmacol.; (United States) Vol. 78; ISSN TXAPA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL GLANDS
ANIMALS
BIOLOGICAL MATERIALS
BIOLOGICAL PATHWAYS
BIOLOGICAL WASTES
BODY
BODY FLUIDS
BROMINATED ALIPHATIC HYDROCARBONS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CLEARANCE
DATA
DIGESTIVE SYSTEM
DISTRIBUTION
ENDOCRINE GLANDS
EXCRETION
EXPERIMENTAL DATA
FECES
GLANDS
HALOGENATED ALIPHATIC HYDROCARBONS
INFORMATION
INHALATION
INTAKE
ISOTOPE APPLICATIONS
KIDNEYS
LIVER
LUNGS
LYMPHATIC SYSTEM
MAMMALS
MATERIALS
METABOLISM
METHYL BROMIDE
NUMERICAL DATA
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
RATS
RESPIRATORY SYSTEM
RODENTS
THYMUS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
UPTAKE
URINE
VERTEBRATES
WASTES