title: Double quantum filtered (1)H NMR spectroscopy enables quantification of lactate in muscle.
abstract: In this study we address the question of quantification of muscle lactate using double quantum filtered (DQF) (1)H NMR spectroscopy where dipolar and scalar coupled spectra are acquired. For this, lactate content in muscle samples was independently determined using a conventional enzymatic assay and DQF, (1)H NMR spectroscopy. NMR quantification of lactate relied on comparison of muscle spectra with similarly acquired spectra of standard lactate solutions. Transverse relaxation, T(2), and dipolar coupling effects were investigated at two different orientations of muscle fibers relative to B(o) and at various lactate concentrations. In all cases, we found a biexponential T(2) decay of the lactate methyl signal with a long T(2) of 142 ms (+/-8 ms, n=24) and a short T(2) of 37 ms (+/-6 ms, n=24). Lactate content of muscle determined by NMR spectroscopy agreed with the results obtained from enzymatic assays of the same samples provided that T(2) effects as well as the presence of both scalar and dipolar coupling interactions of lactate in muscle were taken into account.
authors.affiliation: Department of Bioengineering, University of Washington, 1959 NE Pacific Avenue, Seattle, Washington 98195, USA.
authors.forename: I
authors.initials: I
authors.lastname: Asllani
authors.forename: E
authors.initials: E
authors.lastname: Shankland
authors.forename: T
authors.initials: T
authors.lastname: Pratum
authors.forename: M
authors.initials: M
authors.lastname: Kushmerick
mesh_terms: D000009:Abdominal Muscles / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D019344:Lactic Acid / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy
chemical_list: D019344:Lactic Acid