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R N Kay

Publications and source records attributed to R N Kay.

At least 37 records · Page 2Linked to original sources
PubMed1974

Absorption and catabolism of histamine in sheep.

1. The fate of dietary histamine in sheep has been studied. When 200 mg histamine diphosphate was administered into a rumen with normal contents the average time taken for the biological activity to disappear from the rumen was about 4 hr. In sheep starved for 60 hr the activity disappeared much more slowly.2. When 0.9% NaCl solution was substituted for the normal rumen contents and the rumen was isolated in situ under anaesthesia, the disappearance of histamine was scarcely detectable. About 1% of the radioactivity introduced into such rumen preparations as [(14)C]histamine was recovered in the urine during a 6 hr period.3. When both [(14)C]histamine and 200 mg unlabelled histamine diphosphate were administered into the rumen, between 4 and 15% of the radioactivity and 2 and 11% of the biological activity reached the duodenum.4. When jejunal loops isolated between two pairs of re-entrant cannulas were perfused with 0.9% NaCl solution containing histamine a considerable fraction of the histamine was absorbed from the loops.5. When [(14)C]histamine and 200 mg histamine diphosphate were administered into the rumen an average of 9% of the radioactivity appeared in the urine. When histamine was given into the abomasum the corresponding figure in a single experiment was 25%.6. Between 11 and 34% of the radioactivity administered into the rumen as [(14)C]histamine was exhaled as (14)CO(2). Most of the (14)CO(2) seemed to stem from metabolism of [(14)C]histamine in the ruminoreticulum whereas the contribution of the intestines to (14)CO(2) was very small.7. When [(3)H]histamine was administered into the rumen most of the radioactivity in the urine a few days after administration was in the form of tritiated water. The formation of (3)H(2)O is probably a result of histamine metabolism in the fore-stomach, analogous to the formation of (14)CO(2).

Abomasum↗