Radioautographic Studies of the Digestive Tracts of Rats injected with Inorganic Sulphate labelled with Sulphur-35

BÉLANGER 1 recently reported the presence of sulphur-35 in the neck cells of the gastric glands of the rat following the administration of sulphuric acid labelled with sulphur-35 by subcutaneous injection. We wish to report that we made similar observations during the course of a radioautographic study of the distribution of sulphur-35 in the rat following the administration of radioactive inorganic sulphate. The techniques employed in this work and some of the results obtained have already been reported 2 . Sodium sulphate labelled with sulphur-35 was administered to rats by intraperitoneal injection, and after various intervals the animals were killed, tissues were removed and contact radioautographs were prepared. Four hours after dosing there was considerable accumulation of sulphur-35 in the necks of the gastric glands, whereas radioactive material was absent from that part of the stomach lined with stratified squamous epithelium. More intense radioautographs were obtained from the intestinal glands (crypts of Lieberkühn). The most striking localization of sulphur-35, however, was observed in the small mucus-secreting salivary glands which lie in relation to the masseter muscle and are presumably posterior members of the molar group (Figs. 1 and 2). These results were in marked contrast to those obtained from the adjacent parotid gland present in the same sections, where the intensity of the radioautograph was in general very low, and was less for the actual glandular tissue than for the capsule (Figs. 3 and 4). Other mucus-secreting salivary glands have not yet been investigated.