Search

Comparison of the iron binding capacity of gastric secretion under basal and histamine stimulated conditions showed no significant variation. However, following ‘flushing’ of the gastric mucosa the capacity to bind iron was approximately doubled. Since this procedure is known to cause increased mucus secretion it seems likely that the iron binding capacity in gastric juice is either of mucoid origin or associated with mucus secretion. From what is known of the properties of gastric iron binding the former seems to be the more likely. Furthermore since there is no evidence that iron binding in gastric juice is due to a single component it seems more appropriate to refer to ‘the iron binding capacity’ of gastric juice than to imply by the use of the name ‘Gastroferrin’ that a single entity is involved.

The existence of a specific iron-binding protein (gastroferrin) and the factors affecting the binding of iron to gastric juice were examined in eleven controls and in ten patients with idiopathic haemochromatosis. Binding decreased as iron concentration increased and was also dependent on the assay volume. Similar binding was obtained with other protein solutions and urine. The findings can be best explained by a loose association in which colloidal complexes of iron were maintained in solution by a protective layer of gastric glycoprotein. A more specific iron-binding assay was developed but no significant difference could be found between the two groups, and in the haemochromatosis patients no relationship to iron absorption.

Evidence has been furnished confirming the presence of an iron-binding component gastroferrin, in human gastric juice The unusual iron-saturation curve shown by gastroferrin— increased iron-binding with increased iron concentration but total loss of iron binding beyond a certain concentration-is a consequence of its precipitation with the iron it has been holding in solution. Since carbohydrate but no measurable amount of protein is lost from solution, it seems reasonable to conclude that although gastroferrin may contain some protein it is essentially carbohydrate.