Measurement of 5-hydroxytryptophol and 5-hydroxyindoleacetic acid in human and rat brain and plasma

Abstract

The levels of 5-hydroxyindoleacetic acid (5-HIAA) and free and total 5-hydroxytryptophol (5-HTOL) in human and rat brain regions and plasma were determined by a specific capillary column gas chromatographic-mass spectrometric method. The human brains were obtained 2–3 hourspost mortem, and the levels of 5-HIAA were in the range of 0.48–31.3 nmoles/g in the regions investigated. The levels of free and total 5-HTOL were 10.9–387 pmoles/g and 14.5–821 pmoles/g, respectively. The ratio of total 5-HTOL to 5-HIAA was in the range of 0.6–5.5%. In human plasma the levels of free and total 5-HTOL were 0.9±0.3 and 2.9±0.8 pmoles/ ml±S.E.M., respectively. In regions of rat brain, the 5-HIAA levels ranged from 0.37–2.84 nmoles/g. Free and total 5-HTOL were in the range of 11.4–56.1 and 16.2–77.1 pmoles/g, respectively. The ratio of total 5-HTOL and 5-HIAA ranged from 2.3–5.1%. Higher levels of 5-HIAA and 5-HTOL occurred in the rat pineal gland. In rat plasma the levels of free and total 5-HTOL were 1.34±0.06 and 21.6±1.6 pmoles/ml±S.E.M., respectively.