title: Relationship of serum iron and nonprotein-bound iron concentrations following administration of ferrous sulfate in pigs.
abstract: 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.
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee, Memphis 38163, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Chyka
authors.forename: T D
authors.initials: TD
authors.lastname: Mandrell
authors.forename: J E
authors.initials: JE
authors.lastname: Holley
authors.forename: B E
authors.initials: BE
authors.lastname: Beegle
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005296:Ferrous Compounds / Q000008:administration & dosage / Q000633:toxicity*; D005774:Gastrostomy; D007501:Iron / Q000097:blood* / Q000378:metabolism; D011446:Prospective Studies; D011485:Protein Binding; D017382:Reactive Oxygen Species; D012044:Regression Analysis; D012709:Serum Albumin / Q000378:metabolism; D013054:Spectrophotometry, Atomic; D013552:Swine; D014168:Transferrin / Q000378:metabolism
chemical_list: D001798:Blood Proteins; D003692:Delayed-Action Preparations; D005296:Ferrous Compounds; D017382:Reactive Oxygen Species; D012709:Serum Albumin; D014168:Transferrin; C020748:ferrous sulfate; D007501:Iron