TABLE 2.

Tissue enrichment of ⁵⁸Fe-heme and ⁵⁷Fe-nonheme in rats after gavage with ⁵⁷FeSO₄ and ⁵⁸Fe-RBCs¹

	Nonheme (57Fe)		Heme (58Fe)
	Value	n	Value	n	P2
Blood
Iron excess, %	8.6 ± 1.6	12	3.8 ± 0.5	12	0.0007
Net tracer amount, μg	34.9 ± 6.2	12	1.9 ± 0.3	12	0.0001
Recovered tracer, %	80.5 ± 2.4	11	71.3 ± 4.7	9	0.02
Liver
Iron excess, %	9.5 ± 3.3	11	3.5 ± 1.3	10	0.002
Net tracer amount, μg	6.8 ± 1.1	11	0.41 ± 0.04	10	0.0005
Recovered tracer, %	16.8 ± 2.0	11	21.2 ± 3.7	9	0.15
Spleen
Iron excess, %	1.6 ± 0.5	12	1.2 ± 0.5	10	0.4
Net tracer amount, μg	0.9 ± 0.2	12	0.13 ± 0.03	10	0.002
Recovered tracer, %	2.7 ± 0.6	11	7.5 ± 1.8	9	0.01

¹Values are means ± SEMs unless indicated otherwise. n < 12 indicates lack of tissue sample or presence of nickel contamination that interfered with ⁵⁸Fe determination; a paired t test was performed for rats with data on both variables.

²Paired t test.