Tritiated thymidine autoradiographic study on origin and renewal of gastrin cells in antral area of hamsters.

The origin and renewal of the gastrin cells in the pyloric glands of hamsters were studied by [3H]thymidine autoradiography combined with the immunoperoxidase identification technique. After a single injection of [3H]thymidine, the labeling index of gastrin cells was 0.3%, indicating that a few gastrin cells at the isthmus region have a self-replicating activity. Following pulse labeling after five repeated injections of [3H]thymidine at 6-hr intervals, the labeling index of the gastrin cells showed a linear increase (from 1.2% on the 1st day to 5.2% on the 4th day), and attained a plateau (5.6%) on the 5th day. These findings indicate that most gastrin cells differentiate functionally within 5 days. On the 5th day after the last of 41 injections repeated at 6-hr intervals, the labeling index of gastrin cells was 25.8%, and it decreased gradually as follows: 22.3%, 18.3%, 11.2%, 7.3%, 0.9%, and 0% on the 10th, 15th, 20th, 30th, 50th, and 100th day, respectively. From analysis of this decreasing curve, the turnover time of the gastrin cells (a half-life of the cells) was estimated to be 10-15 days. Spatially. the labeled gastrin cells were at first found in a region from the isthmus to the upper level of the glands and later in the lower level of the glands. This indicates that the gastrin cells arising from immature precursor cells at the isthmus region migrate downwards toward the bottom of the glands.