Beryllium is absorbed mainly through the lungs, where it enters the bloodstream and is transported throughout the body by binding to prealbumins and _-globulins. Beryllium accumulates in lung tissue and the skeleton. It is excreted mainly in the urine. (L25)
Once in the body, beryllium acts as a hapten and interacts with human leucocyte antigen (HLA) DP presenting cells in the lungs, becoming physically associated with a major histocompatability (MHC) class II molecule. This MHC class II-beryllium-peptide complex is recognized by the T lymphocyte receptor, triggering CD4+ T lymphocyte activation and proliferation. The resulting inflammatory response is a cell-mediated process orchestrated by cytokines and results in the formation of (usually pulmonary) granulomas. Beryllium's toxicity may be controlled by the iron-storage protein ferritin, which sequesters beryllium by binding it and preventing it from interacting with other enzymes. (L25, A37, A91)
There is sufficient evidence in humans for the carcinogenicity of beryllium and beryllium compounds. Beryllium and beryllium compounds cause cancer of the lung. There is sufficient evidence in experimental animals for the carcinogenicity of beryllium and beryllium compounds. Beryllium and beryllium compounds are carcinogenic to humans (Group 1). /Beryllium and beryllium compounds/
Beryllium and beryllium compounds are known to be human carcinogens based on sufficient evidence of carcinogenicity from studies in humans. /Beryllium and compounds/
... Skeletal deposition of beryllium from the fluoride ... inhaled for 40 to 100 days by dogs, showed 17% ... retained in lung; 27% ... in liver; & 199% ... in the pulmonary lymph nodes.
Accumulation, distribution, and excretion of inhaled aerosol beryllium fluoride soln was related to the animal's age; 15 min after the exposure, 26.3-33.5% of the inhaled metal was found in the body of adult rats and 2-4 week old rats, and 12.5% in the body of 1 wk old rats. The organ and tissue content varied in animals of different age. Be clearance from the nasal passages, oral cavity, and trachea was slower and Be retention period in the stomach and small and large intestine was longer in 1 wk old rats than in adult rats.
The effects of type of cmpd administered, isotope carrier, and animal development were studied on beryllium absorption from the gastrointestinal (GI) tract of rats. Isotope (7)Be labeled salts, with and without isotope carrier (9)Be (0.25-6 mg/kg), were administered via the stomach. Beryllium accumulation in the liver was 4-12 fold and in the kidney 16-37 fold less than that in the skeleton. The accumulation of beryllium depended on the type of cmpd In 1, 2, and 4 wk old and adult rats, the major amt of beryllium was observed in the skeleton, liver, and kidney. Beryllium chloride administration (with and without the carrier) showed 8 fold higher organ accumulation than that in 1 mo old and adult rats, and beryllium fluoride accumulation was 1.5 fold higher in 1, 2, and 4 wk old rats than that in the adult animals. The isotope carrier had no effect on the level of accumulation in rats of different age groups. Beryllium oxide absorption was higher than that of the hydroxide and beryllium fluoride was absorbed approx 15-20 fold higher than the chloride, sulfate, and nitrate and 210-260 fold higher than the hydroxide. Easily sol cmpd of beryllium are less absorbed presumably due to their hydrolysis in the alk medium of the GI tract. Beryllium fluoride absorption was higher in young animals than that in the adult rats.
