Gastric juice composition

Composition of Various Fractions from Human Gastric Juice ( in % w/w)... 

The existence of more than one mucoprotein in the dissolved mucin fraction of the gastric juice was further substantiated in our laboratory (G26, G27, G36). We found (G27) that the composition of dissolved mucin varied markedly, depending upon the stimulus applied to gastric secretion. These variations included degree of hydration, extractability with 60% alcohol, and content of tyrosine, nitrogen, and reducing substances. We therefore postulated that, in man, at least two but probably three different mucous substances were present within the mixture of mucosubstances called dissolved gastric mucin (Gll, G27) (Fig. 16). 

When 1.5 volumes acetone is added to the trichloroacetic acid filtrate of the gastric juice, an abundant flocculent precipitate forms, which contains all the components of dissolved mucin with the exception of soluble mucus. If this precipitate is taken up in dilute alkali and then acidified with dilute HCl down to pH 3.5, a fine flocculent precipitate forms, which we named dissolved mucoprotein (G27, G36). It was later renamed glandular mucoprotein (G9, G38) because of its close relationship to the fundic glands of the stomach. This material contained much protein its nitrogen content was 12.61 0.44% and its tyrosine content 7.50 0.65% by the Folin-Giocalteu reaction. The reducing substance content was 6.38 1.48% before and 12.5% after hydrolysis (G9, G27, G36) (see Table 4). Werner (W9) determined the composition of this mucoprotein fraction and found that it contained 11.2% N by Kjeldahl, 8.8% hexosamine, 4.8% uronic acid, and 2.0% sialic acid. 

Other workers determined the entire carbohydrate spectrum of human gastric juice in an attempt to evaluate the composition of gastric mucosubstances. Richmond et al. (R4) and Hoskins and Zamcheck (H50) studied a large number of individual gastric juices in our laboratory (G55) a large pool of normal gastric juices was studied for hexoses, hexosamine, fucose, sialic acid, uronic acid, and total carbohydrate content. Results obtained in normals and patients with various gastric diseases are summarized in Tables 8 and 9. 

The composition of various blood group substances from human gastric juice, as reported by Masamune et al. (M22), Tiba (T29) and Yosizawa (Y3), varies only little. The N content is in the range 4.7-4.9%, hexos-amine 29.0-30.8%, galactose 26.6-27.8%, fucose 12.9-14.1%, and sialic acid 3.0-5.2%. Presence of considerable amounts of sialic acid in these materials perhaps indicates their contamination with sialomucin. 

In work from our laboratory, Ibanez determined the composition of the first fractions eluted from the Amberlite IRC-50 column of gastric juice pools from indh iduals with various blood groups. The first fraction eluted with citrate of pH 3.2-S.5 is known (R4, R4a) to contain blood group substances. 

Fig. 10. Electrophoretic pattern (average of 27 runs) and composition of elutes from 30 identical segments 5 miti wide of 354 paper electrophoretic runs of a pool of human gastric juice (457 mg dry weight). From Class et al. (G16).

Takamura et al. and Wada et gastric juice of normal individuals and patients with histamine-fast anacidity and gastric carcinoma by continuous electrophoresis on paper curtain, and assayed the chemical composition and biological activities of the fractions obtained. Electrophoresis was performed in veronal buffer of pH 8.6 and ionic strength of 0.03, at 225 volts and 7.5-8.25 mA for 24 hours. As in paper strip electrophoresis, 4 major components were obtained, named by the authors (from anode to cathode) Bl, B2, B3, and B4 B3 contained three minor components A, B, and C. In addition, acidic gastric... 

Electrophoretic analysis of hog intrinsic factor concentrates has been extensively used for characterization of their composition (C6, E1-E3, G2, Gil, G29, G30, Hll, Jl, W14, W15). The discussion of these findings would exceed the limits of this review and the reader is referred to the author s review on intrinsic factor (G4). Hurlimann (H20) studied by autoradiography vitamin B12 binders in the gastric juice and confirmed the presence of two binders of different electrophoretic mobility (see Fig. 29). 

V. —Amyloid — is a pathological product, occurring in fine grains, resembling starch-granules in appearance, in the membranes of the brain and cord, in waxy and lardaceous liver, and in the walls of the blood-vessels. Its composition is that of the albuminoids, from which it differs in being colored red by iodin violet or blue by iodin and HjSOt. Soluble in HCl with formation of syntonin and in alkalies. It is not attacked by the gastric juice, and is not as prone to putrefaction as the other albuminoids. 

Influence of Feeding on the Quantity and the Composition of the Gastric Juice Secreted. — First of all, it has been established that there exists a very definite relation between the secretorial functions and the food absorbed. Thus Chigin, by measuring the quantity of gastric juice which flows after the ingestion of various foods, has found ... 

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