title: Measuring plasma fatty acid oxidation with intravenous bolus injection of 3H- and 14C-fatty acid.
abstract: Accurate measures of plasma FA oxidation can improve our understanding of diseases characterized by impaired FA oxidation. We describe and compare the 24 h time-courses of FA oxidation using bolus injections of [1-(14)C]palmitate versus [9,10-(3)H]palmitate under postabsorptive, postprandial, and walking conditions. Fifty-one men and 95 premenopausal women participated in one condition (postabsorptive, postprandial, or walking), one tracer ((14)C- or (3)H-labeled), and an acetate or palmitate study. Groups were matched for sex, age, and body mass index (BMI). At 24 h, cumulative [(3)H]acetate recovery as (3)H(2)O was 80 ± 6%, 78 ± 2%, and 81 ± 6% in the postabsorptive, postprandial, and walking conditions, respectively (not significant). Model-predicted maximum [1-(14)C]acetate recovery as expired (14)CO(2) was 59 ± 12%, 52 ± 8%, and 65 ± 10% in the postabsorptive, postprandial, and walking condition, respectively (one way ANOVA, P = 0.12). When corrected with the corresponding acetate recovery factors, 24 h time-courses of FFA oxidation were similar between [1-(14)C]palmitate and [9,10-(3)H]palmitate in all three conditions. In contrast to previous meal ingestion studies, an acetate-hydrogen recovery factor was needed to achieve comparable oxidation rates using an intravenous bolus of [(3)H]palmitate. In conclusion, intravenous boluses of [9,10-(3)H]palmitate versus [1-(14)C]palmitate gave similar estimates of 24 h cumulative FFA oxidation in age-, sex- and BMI-matched individuals.
authors.affiliation: Endocrine Research Unit, Mayo Clinic, Rochester, MN, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Koutsari
authors.forename: Asem H
authors.initials: AH
authors.lastname: Ali
authors.forename: Manpreet S
authors.initials: MS
authors.lastname: Mundi
authors.forename: Michael D
authors.initials: MD
authors.lastname: Jensen
mesh_terms: D000042:Absorption; D000085:Acetates / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000378:metabolism*; D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods*; D002250:Carbon Radioisotopes / Q000737:chemistry; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D010084:Oxidation-Reduction; D010168:Palmitates / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000378:metabolism*; D019518:Postprandial Period; D011854:Radiochemistry; D013997:Time Factors; D014316:Tritium / Q000737:chemistry*; D016138:Walking
chemical_list: D000085:Acetates; D002250:Carbon Radioisotopes; D010168:Palmitates; D014316:Tritium