The fate of indolethylamine in the organism / by A.J. Ewins and P.P. Laidlaw.

  • Ewins, Arthur James.
Date:
1913
Catalogue details

Licence: In copyright

Credit: The fate of indolethylamine in the organism / by A.J. Ewins and P.P. Laidlaw. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    We had already shown [Ewins and Laidlaw, 1910] that it was possible to obtain this base by the action of putrefactive bacteria on tryptophane; but the method is tedious and troublesome, and the yield very poor. We have carried out two sets of experiments in the course of our investigation: (1) feeding experiments on dogs, and (2) the perfusion of surviving livers of rabbits and cats1. Perfusion Experiments. The method of perfusion was similar to that already described in our paper dealing with the fate of jj-hydroxyphenylethylamine [Ewins and Laidlaw, 1910]. Small quantities of indolethylamine were perfused through surviving livers for 3—4 hours. The perfusion fluid gradually acquired the property of giving a fine red colour, when it was mixed with one-third of its volume of strong hydrochloric acid, with the addition of one drop of dilute ferric chloride, and then boiled. The red colour occasionally had a faint blue component if the hydrochloric acid was in excess or if the boiling was prolonged. A cherry red colour also developed if a trace of sodium nitrite was substituted for the ferric chloride in the above tests. Amyl alcohol rapidly extracted the pigment from the solution, when a well-defined absorption band in the green was seen with a spectroscope. The red colour is brighter and purer and the absorption band more intense and better defined when sodium nitrite is used. When the chromogen of the pigment appeared to be fairly abundant in the perfusion fluid (usually about 3-4 hours) the perfusion fluid was collected, and the liver vessels washed through with salt solution. The combined washings and perfusion fluid were rendered faintly acid with acetic acid and boiled. The coagulated proteins were filtered off and the filtrate evaporated to small bulk. The concentrated perfusion fluid was made acid to Congo-red with strong hydrochloric acid and shaken out with ether, which readily and completely extracted the chromogen. The ethereal extracts were combined, washed twice with water and taken to dryness. If the residue were taken up in water and allowed to stand, a small quantity of a crystalline acid was regularly obtained, which when recrystallised from benzene melted at 163-164°. These crystals gave the colour reactions mentioned above with great intensity and readily gave a deep orange-red coloured picrate melting at 174°. These properties taken together are characteristic of indoleacetic acid. 1 The animal experiments were performed by P. P. Laidlaw only.