A practical assay of lipoate in biologic fluids and liver in health and disease

• Published in: Free radical biology & medicine Vol. 25; no. 4; pp. 473 - 479
• Main Authors: Baker, Herman, Deangelis, Barbara, Baker, Elliott R., Hutner, Seymour H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-09-1998
• Subjects: Absorption; Adult; Animals; Biological Assay; Body Fluids - chemistry; Free radicals; Humans; Kidney Diseases - metabolism; Kinetics; Lipoate absorption; Lipoate in biologic fluids and tissues; Lipoic Acid assay; Liver - chemistry; Liver Diseases - metabolism; Middle Aged; Reference Values; Tetrahymena thermophila - drug effects; Tetrahymena thermophila - growth & development; Thioctic Acid - analysis; Thioctic Acid - blood; Thioctic Acid - pharmacokinetics; Lipoic Acid assay; Lipoate in biologic fluids and tissues; Free radicals; Lipoate absorption
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/S0891-5849(98)00087-2

A procedure for assaying lipoic acid concentration in biologic fluids and tissues was devised using a eukaryotic protozoan
Tetrahymena thermophila.
T.thermophila has a specific and sensitive (30 pg/ml) requirement for lipoic acid. Unlike humans and other microorganisms,
T.thermophila can not synthesize lipoic acid; hence, its requirement for exogenous lipoic acid is specific. The lipoic acid supplied to
T.thermophila by the processing of biologic fluids and tissues during the assay procedure, permits the derivation of a practical assay for lipoate concentration as described here. Lipoate concentration in biologic fluids and tissue obtained from healthy humans, compared to those obtained from patients with renal and liver disease, indicate deviations from normal during disease. Absorption chartings of 200 mg of DL-α-lipoic acid in humans indicate a peak concentration of lipoate in plasma 2 h after ingestion and then a steady descent of lipoate to a baseline level after 24 h. With this practical assay, it is now possible to chart lipoate’s antioxidant activity and therapeutic action during health and disease.