Relationship of serum iron and nonprotein-bound iron concentrations following administration of ferrous sulfate in pigs
Chyka, P.A.; Mandrell, T.D.; Holley, J.E.; Beegle, B.E.
Veterinary and Human Toxicology 38(1): 24-26
1996
ISSN/ISBN: 0145-6296 PMID: 8825744 Document Number: 460292
A prospective analytical study was conducted to determine the relationship between nonprotein-bound iron and serum iron concentrations following gastric instillation of ferrous sulfate. Four female pigs (20-22 kg) with indwelling central venous lines and gastrostomy tubes were studied. A 5% solution of ferrous sulfate (20 mg elemental iron/kg bwt) was administered through the gastrostomy tube over 1 to 2 min. Six hourly blood samples were collected, and serum samples were subjected to ultrafiltration with the filtrate representing nonprotein-bound iron. Iron concentrations were determined by atomic absorption spectrophotometry. Baseline (mean +/- SD) iron concentrations were 73 +/- 25 micrograms/dL as the serum total and 21 +/- 4 micrograms/dL as nonprotein-bound iron. The serum iron and nonprotein-bound iron concentrations achieved a peak of 191 +/- 66 and 23 +/- 10, respectively, at 2 h and declined to near baseline values at 6 h. The mean ratio of filtrate to serum iron concentration was 0.16 +/- 0.08 and ranged from 0.08 to 0.29. Nonprotein-bound iron did not increase as the serum iron concentration increased (r = 0.18) within the ranges achieved in the study. The absence of protein, particularly transferrin and albumin, was verified by electrophoresis. A form of apparent nonprotein-bound iron was isolated from serum by ultrafiltration and its concentration was relatively constant despite the rise and fall of total serum iron concentrations during the 6 h. These observations warrant further investigation to understand the development of toxicity in acute iron poisoning.