Masters Theses

Date of Award

3-1942

Degree Type

Thesis

Degree Name

Master of Science

Major

Chemistry

Major Professor

E.F. Williams

Abstract

A number of substances are known which stimulate gastric secretion either when introduced into the lumen of the stomach or intestine, or when injected intravenously or intramuscularly. Among substances that have been tested experimentally by direct introduction into the stomach and have been found active as stimulating agents are beta-alanine, histamine, adrenaline, and peptone (1).

Substances which affect gastric secretion following their intramuscular or intravenous injection act through a humoral mechanism. Among compounds which have been tested for such effect are: Histidine. This has no effect on gastric secretion (2). Choline. Intravenously it weakly stimulates volume and acid (3). Lacithin. Its action is similar to that of choline (3). Acetyl-beta-methyl-choline. This was found to be inactive (4). Bromcholine. Following subcutaneous injection gastric stimulation occurred, but the flow of juice was slower and contained less acid than following a comparable injection of histamine (5). Cystamine. It produced an acid gastric secretion when injected intramuscularly (6). Pilocarpine. Intravenous injection of the substance stimulated gastric secretion, and its action was inhibited by atropine (7). "Acaprine." Subcutaneously injected it caused an increase in the flow of gastric juice (8). Histamine. When injected intramuscularly this is a very effective gastric secretagogue (9). "Gastrin." Intramuscular injection of an aqueous acid extract of gastric mucosa causes the secretion of a greater volume of gastric juice with a higher concentration of acid than before injection (10).

Extracts of three natural vegetable materials have been shown to have a stimulating effect on gastric secretion. Using spinach, Bickel (11) prepared an active extract which was stable to dry heat up to about 140 degrees C and also to boiling with concentrated hydrochloric acid. Gleichmann (12) found filtered tomato juice to be active when injected intramuscularly. Williams, Cox and Nash (9) prepared a yeast extract which stimulated the previously resting stomachs of dogs.

Since the last mentioned report showed that the active substance could be concentrated from a hot acid-aqueous extract of yeast, it was the purpose of the studies reported in this thesis to purify the extract further and to isolate and identify the active principle if possible.

The primary approach to the problem was to devise a more efficient and facile method of extraction and this was found in the acid-alcohol extraction of dry yeast. Since this gave a reliably active extract, the procedure of differential solubilities in the major organic solvents was followed as a possible means of purification and identification.

A still further approach was made by testing various organic compounds for their activity on gastric secretion, the hope being that the active substance in yeast might be identical with one of them. The compounds were selected on the basis of their known presence in yeast or their suspected presence as indicated by the results of extraction and separation procedure.

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