[Effects of human chorionic gonadotrophin and progesterone on small intestinal migrating myoelectric complex in rats]

The effects of human chorionic gonadotrophin (HCG) and progesterone (P) on migrating myoelectric complex (MMC) of the small intestine in ovariectomized rats were investigated by implanted monopolar-electrode in the intestinal wall of the duodenum, jejunum and ileum. The results showed (1) after i.v. administration of HCG the periodicity of the duodenal and upper jejunal MMC was interrupted by irregularly prolonged phases II occurring intermittently; (2) after i.m. administration of P the duration of phases I and II of the duodenal MMC was significantly prolonged, but the periodicity was not affected; (3) the effect of P plus HCG on MMC was similar to that of HCG alone, but the combined effect was spread over the whole small intestine. These results suggest that HCG can induce remarkable changes of the small intestinal MMC, which are similar to those observed in pregnant rats. In the presence of P, the effect of HCG is enhanced markedly.