Absorption of histamine from the gastrointestinal tract of dogs in vivo

Abstract

1. In anaesthetized dogs, various amounts of [(14)C]histamine were introduced into the lumen of a ligated intestinal loop or of the ligated stomach and the absorption of this histamine was studied by determining the radioactive histamine in the venous blood coming from the ligated part.2. After the introduction of 5-5000 mug [(14)C]histamine, into a loop of jejunum, or of 50 mug into a loop of duodenum, ileum or colon, radioactive histamine was detected in all eight successive 15 min samples of venous blood collected during 2 hr. The percentage recovery of the [(14)C]histamine in the blood during this period varied between 0.04 and 3.7.3. After the introduction of 10 mg [(14)C]histamine into the stomach, radioactive histamine was detected in all samples of gastric venous blood collected at various times during the following 4 hr.4. After the introduction of 50-5000 mug [(14)C]histamine into a loop of jejunum, radioactive histamine was also detected in the general arterial blood.5. When a jejunal loop was perfused through its artery with a dextransaline solution, the absorption of [(14)C]histamine from the lumen into the venous effluent was much greater than when the blood supply was kept intact.6. A large part of the [(14)C]histamine introduced into an intestinal loop was inactivated or destroyed either in the lumen or the wall since only a part was recovered in the venous blood, contents and wall of the loop at the end of 2 hr. When different amounts of [(14)C]histamine were introduced into a jejunal loop the recovery was shown to be dependent on the dose. With 5 mug it amounted to about 1% whereas with 5000 mug to 29-42%. The recovery of the [(14)C]histamine introduced into a perfused jejunal loop was greater.7. In dogs and cats large amounts of free histamine were found in the contents of the stomach 2 hr after a meat meal, and much smaller amounts in the contents of loops from the small intestine. The amounts found in the contents of loops from the colon varied greatly.8. In eighteen commercial dog and cat foods the free histamine contents were found to vary over fiftyfold, from 0.06 to 3.5 mg/100 g.9. The significance of the results is discussed in relation to the role of histamine as a humoral agent in the ;gastric' and ;intestinal phases' of gastric secretion.

Absorption and catabolism of histamine in sheep

“…None the less, it is probable that some intestinal absorption takes place since histamine given orally or administered into isolated segments of the intestine raises the concentration of free histamine in the blood (Duncan & Waton, 1968) and urine (e.g. Millican, Rosenthal & Tabor, 1949;Livingston & Code, 1955;Irvine, Duthie, Ritchie & Waton, 1959).…”

Metabolism and Distribution of Exogenous Histamine in Cats

“…These results are consistent with the role played by the small intestine in amine absorption. In contrast, Duncan & Waton (1968) found radioactive histamine in blood from both the small intestine and stomach following instillation of [14C]-histamine into these sites in dogs. Even allowing for species variation this is a surprising result since in the acidic milieu of the stomach, histamine would be mainly ionized and therefore not expected to cross the stomach wall.…”

“…These results are consistent with the role played by the small intestine in amine absorption. In contrast, Duncan & Waton (1968) found radioactive histamine in blood from both the small intestine and stomach following instillation of…”

“…Thus with the smaller doses (1.7 and 5 gmol/kg), histamine accounted for 12 to 15% of the total radioactivity during the 30 min after instillation compared with about 40% (4 cats) after the largest dose (82 gmol/kg). Absorption of small amounts of histamine into portal blood, also described by Duncan & Waton (1968) in dogs, may be of importance since the quantities absorbed were sufficient to elicit acid secretion from a pentagastrinsensitized stomach (Waton, 1973). Certainly, absorption of these amounts in cats is feasible because of the quantities of histamine in cat and dog foods (Duncan & Waton, 1968).…”

“…Absorption of small amounts of histamine into portal blood, also described by Duncan & Waton (1968) in dogs, may be of importance since the quantities absorbed were sufficient to elicit acid secretion from a pentagastrinsensitized stomach (Waton, 1973). Certainly, absorption of these amounts in cats is feasible because of the quantities of histamine in cat and dog foods (Duncan & Waton, 1968). The large amounts of ["4C]-histamine found in portal blood of two cats after histamine (82 gmol/kg), 70% of total radioactivity recovered, may explain the toxic effects occasionally seen in man after ingestion of histamine-containing foods and tentatively attributed to histamine (Ienistea, 1971).…”