Amines and metabolites

Adrenaline, Waldi [177] describes the semi-quantitative determination of acetylated adrenaline and noradrenaline, using TLC. Segijra-Cardona and Soehring [149] have separated very small amounts of catechol amines and derivatives on polyamide layers. The lower limit of detection for adrenaline is about 0.003 [xg. 

10—20 ml of the 24 hour-urine are adjusted to pH 0 with cone. HCl, saturated with NaCl and extracted by rhorough shaking with three 50 ml portions of diethyl ether. The ether extract is evaporated to dryness, the residue dissolved in 1 ml ethanol and 0.1 ml of this solution is applied to the layer (adsorbent = 25 g silica gel G + 25 g kieselguhr G + 2.5 g fluorescent pigment ZS super + 90 ml water layer thickness 250 (xm dried 1 h at 105° C). This is developed at chamber saturation with isopropanol-ethyl acetate-ammonium hydroxide-water (45 + 30 + 17 

5-Hydroxyindoleacetic acid. This acid (5-HIA) is the degradation product of serotonine (5-hydroxytryptamine). Urinary elimination of over 15 mg per day renders probable the diagnosis of a metastasising carcinoid, provided the influence of diet (bananas, walnuts etc.) is excluded. Standard amounts of 5-HIA and increasing amounts of the urine extract are applied to the adsorbent in the semi-quantitative determination of Schmid and Kuschke [143]. After the TLC-separation, the plate is sprayed, with 0.1% 2,6-dichloroqiiinonechloroiniide solution in methanol and the spot sizes compared in the approximate evaluation. Especially distinct, brownish-red spots are obtained by spraying with diazotised p-nitroaniline (Fig. 173). This reaction also can be adapted to quantitative determination [143 a]. 

Methylhistamine, Fram and Green [47] have detected methyl-histamine as histamine metabolite in normal urine. The dinitrophenyl-methylhistamine was separated by TLC on a silica gel G layer and photometrically determined at 358 nm after elution. 

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Fig. 3. Metabolism of noiepinephiine and epinephiine (see Table 2 for abbreviations of amines and metabolites and CAS Registry Numbers).

Kanada M, Miyagawa M, Sato M, et al. 1994. Neurochemical profile of effects of 28 neurotoxic chemicals on the central nervous system in rats (1) effects of oral administration on brain contents of biogenic amines and metabolites, hid Health 32 145-164. 

Baker, G.B. and Reynolds, G.P. (1989) Biogenic amines and metabolites in Alzheimer s disease noradrenaline, 5-hydroxytryptamine and 5-hydroxyindole-3-acetic acid depleted in hippocampus but not in substantia innominata. Neurosci. Lett. 100 335-339. 

Fig. 5. Possible approaches to LC measurements of brain amines and metabolites.

Desimio [5] has reported that biogenic amines can be separated on silica gel 6 layers, using the solvent mixture, commonly employed in PC, of n-butanol-acetic acid-water (66 -f 17 + 17). 6-Hydroxycatechol amines and metabolites can be separated also with the same solvent or with n-butanol-25% ammonium hydroxide-ethyl acetate (60 + 20 + 20) [4a]. 

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