Histamine forming capacity

Lung (in vitro) Histamine forming capacity Allen et al., 1996... 

H3 receptor activation in the airway system of the guinea pig caused a decrease in histamine release from mast cell and/or basophils and the H3 antagonist had the opposite effect. As far as histamine synthesis is concerned, the allergen-exposure induced histamine forming capacity could be increased by thioperamide, even though (R)a-methylhistamine was completely inactive. The explanation given for this peculiar phenomenon was that the histamine... 

Allen, M.C., Graham, P., Morris, G., 1996. Histamine forming capacity (HFC) and its modulation by H3 receptor ligands in a model of bronchial hyper-responsiveness. Inflamm. Res. 45, 118-122. 

It is possible for a tissue to have a low or impaired histamine-forming capacity (HFG) and yet to have a high histamine content by virtue of its ability to store the amine. Thus in rats subjected to prolonged inhibition of histamine formation by means of a pyridoxal-deficient diet , the HFC in abdominal skin, tongue and lung was reduced to less than 10 per cent of normal without diminishing the histamine content. In the gastric mucosa,... 

The peak of histidine decarboxylase activity in foetal rat liver coincides. approximately with that of haemopoietic activity . Subsequently, the bone marrow of the adult rat was found to contain a specific histidine decarboxylase Table 4.4), thus supporting the possibility of a connection between haemopoiesis and the formation of histamine . Histidine decarboxylase also occurs in the bone marrow of the guinea-pig this enzyme activity, which was shown to be related to the number of basophils, does not, however, support a relationship between histidine decarboxylase activity and growth, since the basophils in the buffy layer of guinea-pig blood have also a considerable histamine-forming capacity, but contain no cells in mitosis . ... 

Note. The effect of sex hormones on the histidine decarboxylase activity of tissues has not been systematically examined, but the administration of oestradiol to ovariectomized female mice produces a substantial increase in the histamine-forming capacity of the liver . 

Here I must insert a warning. Almost all the work on the relation of histamine forming capacity to the control of acid secretion has been done on rats. Histamine does stimulate acid secretion in the rat, but compared with man and the dog, the doses of histamine required are enormously high, and perhaps histamine metabolism in the rat in relation to acid secretion is not identical to that in other species. 

A model of histamine synthesis and mobilization in the gastric mucosa, as described by G. Kahlson in 1964. He postulated a feedback control of the histamine-forming capacity (HFC) of the mucosa by the histamine content of the mucosa itself. Some 30 years later, the validity of this prescient suggestion appears substantiated by the identification of different histamine receptor subtypes on the enterochro-maffin-like cell and their ability to regulate histamine secretion. 

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