Abstract
It was shown 1 that commercial gastric mucin when subjected to peptic digestion and subsequent precipitation with alcohol at 70% concentration, yielded upon hydrolysis characteristic values for total nitrogen and total reducing substances. This suggested the use of a reduction method for the quantitation of mucin. Obviously before such a method can be applied to gastric juice, it is necessary to remove all other reducing substances, or to use a procedure for obtaining gastric juice not subject to their presence. The former procedure would be capable of wider application and work is in progress with this end in view. Our present interest is in the variations in mucin content of gastric secretion, when juice is obtained from the fasting stomach by means of an alcohol test meal under conditions excluding other reducing substances.
In following the curve of mucin secretion, the stomach is emptied after a night's fast, basal secretory rate established, then 250 cc. of 7% ethyl alcohol is given and samples removed through a Rehfuss tube at 15 minute intervals for a period of 2 hours. Determinations of total and free acidity, and pepsin, are made. The mucin secretion is followed by the determination of total reducing substances according to the following method: The gastric sample (5 cc. if available) is diluted with an equal volume of 4 N H2SO4. It is then hydrolyzed in a boiling water bath for 2 ½ to 3 hours using an air condenser. After cooling, 2 cc. aliquot samples are pipetted into test tubes, the acidity neutralized to phenolphthalein with 1 N KOH or NaOH, and the reduction estimated by the Somogyi modification of the Shaffer-Hartmann method. 2 The results are expressed in milligrams of reducing substances (calculated as glucose) per cubic centimeter of gastric juice.
To illustrate values found, the accompanying graphs are appended.
Get full access to this article
View all access options for this article.