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Histamine reduces the deamination of putrescine in vitro--but also in vivo?
Agents and Actions
|April 1, 1985
Abstract:
The diamine oxidase catalysed deamination of putrescine was reduced in vitro by histamine at concentrations occurring in the gut. An oral application of histamine, however, had no effect on the enzymic activity. When the histamine was injected i.p. a decrease of intestinal diamine oxidase activity was observed which, however, did not depend on histamine but probably on an unspecific irritation of the gut.
Insights
Histamine inhibits diamine oxidase activity in vitro, but not after oral administration. Intraperitoneal injection decreased enzyme activity due to irritation, not histamine itself.
Area of Science:
- Biochemistry
- Pharmacology
- Gastroenterology
Background:
- Diamine oxidase (DAO) is crucial for metabolizing biogenic amines.
- Histamine is a biogenic amine found in the gut.
- DAO activity is essential for maintaining gut homeostasis.
Purpose of the Study:
- To investigate the effect of histamine on diamine oxidase (DAO) activity.
- To determine if histamine affects DAO activity in vitro and in vivo.
Main Methods:
- In vitro assays measuring DAO-catalyzed putrescine deamination.
- In vivo studies involving oral and intraperitoneal administration of histamine in animal models.
Main Results:
- Histamine inhibited DAO activity in vitro at physiological gut concentrations.
- Oral histamine administration did not alter intestinal DAO activity.
- Intraperitoneal histamine injection led to decreased DAO activity, likely due to non-specific gut irritation.
Conclusions:
- Histamine's inhibitory effect on DAO is demonstrated in vitro.
- In vivo administration routes influence histamine's impact on DAO activity.
- The observed in vivo reduction in DAO activity is not directly mediated by histamine but by inflammatory responses.