In order to observe the regulative effects of pentagastrin (PG) and somatostatin (SS) on the growth of two human gastric cancer cell lines (HGC803 and HGC823) in vitro, we observed the effects of PG and SS on proliferation of human gastric cancer cells by means of MTT. The contents such as gastrin, insulin, and glucagon were determined by radioimmunoassay (RIA), and the hexosamine content was determined by Neuhaus' method. The results showed that the growth of the two human gastric cancer cell lines were obviously promoted by PG. On the contrary, the growth and secretion of gastrin and glucagon were inhibited by SS. In addition, the hexosamine content of human gastric cancer cells was significantly increased by PG (7.58 +/- 0.66 versus 4.20 +/- 0.39 pg/cell, (P < 0.05). But the hexosamine content was decreased by SS (2.62 +/- 0.29 versus 4.20 +/- 0.39 pg/cell, P < 0.05). These findings indicate that the growth of gastric cancer cells is regulated by PG and SS, nevertheless a host of problems need to be elucidated.