OBSERVATIONS ON THE INCORPORATION OF ³⁵S IN DUODENAL MUCOSUBSTANCES

¹ The Department of Biochemistry, Oxford
² The Sir William Dunn School of Pathology, Oxford

1. A method is described for preparing and collecting juice from duodenal fistule in rabbits.

2. Intravenous injection of Na₂³⁵SO₄ into rabbits results in the rapid appearance of ³⁵S in duodenal mucous secretion obtained from fistulæ or in acute experiments.

3. Such secretion contains ³⁵SO₄^2-, mucosubstances containing ³⁵S-sulphate ester groups, and a dialysable ³⁵S-sulphate ester of unknown structure.

4. The proportion of ester ³⁵SO₄ to ³⁵SO₄^2- in duodenal secretion reaches a steady value 9 hours after injection of the isotope, the radioactivity of the blood having fallen to a very small value at this time. It is suggested that the mucous glands have the capacity to store ³⁵SO₄^2- in some form.

5. Injection of ³⁵S-methionine results in the incorporation of the amino-acid into the mucosubstances. No evidence of its conversion to ³⁵SO₄^2-was found in the duodenal secretion.

6. Cortisone has some slight effect on the incorporation of ³⁵SO₄^2-, but none on that of ³⁵S-methionine, into epithelial mucosubstances of the rabbit duodenum.

Note:

We are indebted to the Medical Research Council for the award of a Studentship (M. W. W.) and for a grant for personal assistance (P. W. K.). We are most grateful to Mr. C. A. Pasternak and Miss M. Hiscock for their help in the chemical work, and to Mr. J. Kent for his constant care of the animals and assistance with the operations and collections. The drawings were made by Miss C. Court. The cortisone used for this work was supplied by the Medical Research Council.