Trace Elements and Electrocytes.(1994) Volume 1, Issue 4. P.182-186.
Comparative retention/absorption of 51chromium (51Cr) from 51Cr chloride, 51Cr nicotinate and 51Cr picolinate in a rat model
K. L. Olin ; D. M. Stearns ; W. H. Armstrong ; C. L. Keen
Recently, there has been a renewed interest in better defining the metabolism of chromium (Cr) with respect to both its absorption and cellular action. In the current study we investigated the absorption/retention of 3 Cr(III) compounds (Cr chloride [CrCl], Cr nicotinate [CrNic], Cr picolinate [CrPic]) over a 12 h period in a rat model. Male rats (150 – 170 g) were gavaged with 44 μCi (2.7 nmoles) 51Cr as CrCl3 x 6H2O, CrNic or CrPic. Rats were killed at 1, 3, 6, and 12 h post-gavage. Cardiac blood was collected and liver, kidneys, pancreas, testes, and gastrocnemius were removed, weighed and assayed for 51Cr. The amount of51Cr in these tissues, along with that in urine (collected for the 6 and 12 h groups), was used to calculate 51Cr absorbed/retained. Urine, followed by muscle and blood, had the highest percent of absorbed/retained counts. For the majority of the time points and tissues, the average percent 51Cr retained was higher in CrNic-gavaged rats than in CrCl- or CrPic-gavaged rats. Tissues collected 1 h post-gavage from CrNic rats had retention percentages that were 3.2 to 8.4- fold higher than in the CrPic or CrCl groups. Three h post-gavage, CrNic rats had blood, muscle, and pancreatic 51C tentions that were 2.4 to 8 times higher than CrPic-gavaged rats. By 6 and 12 h post-gavage, the ‘absorbed/retained’ tissues were 1.8 to 3.8 times higher in CrNic than in CrPic rats. It is evident from the above that when investigating the absorption/retention of Cr, it is critical to evaluate urinary 51Cr activity, which reflects absorbed Cr, and early time points. The results show that there can be significant differences in the bioavailabillty of different Cr compounds.
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