The proliferative kinetics of somatostatin-producing cells in the rat antral mucosa after truncal vagotomy.

The kinetics of somatostatin-producing cells (D-cells) in the rat antral mucosa after truncal vagotomy were studied using double immunostaining for bromodeoxyuridine (BrdU) and somatostatin. Both the concentration of somatostatin and D-cell density in the antral mucosa demonstrated a significant increase on the 3rd day after truncal vagotomy. With the single labeling of BrdU, a few D-cells showed positive immunostaining for BrdU throughout the experimental period in both vagotomized and sham operated rats. With cumulative labeling, the BrdU labeled cells demonstrated a linear increase in an identical number for each experimental time-point in both groups. The labeling index of BrdU in the D-cells increased significantly, beginning on the 3rd day and attaining a maximum level of 41.8% on the 10th day, in the vagotomized group after cumulative labeling. In this group, however, the density of D-cells with no immunoreactive BrdU also increased quickly on the 3rd day with cumulative labeling. The present study indicates that the most important factor involving D-cell hyperplasia observed after truncal vagotomy is the activation of pre-existing D-cells to synthesize and release hormones, together with the rapid replication of progenitor cells and their maturation to D-cells.