Author
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Uthus, Eric |
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Submitted to: Experimental Biology
Publication Type: Abstract Only Publication Acceptance Date: 4/17/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Male weanling Sprague-Dawley rats were fed a skim milk-based diet containing 0 or 1 ug Ni (as NiCl2 6H2O)/g. After 62 days, the rats were given an oral dose of 63**Ni (10.7 uCi 63**Ni as NiCl2, specific activity: 12.7 mCi/mg Ni; l0.84 ug Ni/10.7 uCi). After dosing, 6 rats from each dietary treatment were placed in metabolic cages for urine and feces collection. The remaining rats (14 per group) were killed at various time points (15 min to 7 days) after dosing. After whole-body perfusion with saline, organs were removed, weighed, digested with HNO3-H2O2 and counted for 63**Ni. Data were modeled by using SAAM II. Based on 7-day cumulative excretion, Ni-deprived rats absorbed 4.5% of the dose whereas the Ni- supplemented rats absorbed 2.5%. After 7 days, 1.3% of the dose was excreted in the urine of the Ni-deprived rats and 2.4% by the Ni- supplemented rats. For liver, peak 63Ni counts occurred within 30 min of dosing; the peak for the Ni-deprived rats was higher than that of the Ni- supplemented rats (0.15% vs 0.09% of dose). The peak of 63**Ni counts in whole blood, kidney, and bone was broad for both groups and occurred between 30 and 180 min. Peak counts for whole blood represented approximately 0.07% of the dose in the Ni-deprived rats and 0.06% in the Ni-supplemented group. Regardless of dietary group, peak counts for kidney represented about 0.04% of the total dose and only about 0.001% of dose for bone (femur). Three compartments were necessary to approximate the data for each tissue modeled. These findings indicate that the homeostatic regulation of Ni in a rat can be affected by dietary Ni and that more Ni is absorbed and less excreted as a result of Ni deprivation. |