DELAYED GASTRIC-EMPTYING IN CONSCIOUS MALE-RATS FOLLOWING CHRONIC ESTROGEN AND PROGESTERONE TREATMENT

Several clinical observations and animal experiments have led to specu lation concerning the possible effects of pregnancy and pregnancy-asso ciated sex steroids on gastrointestinal function. It was reported that estrogen increases intestinal contractile activity, while progesteron e or the combination of estrogen and progesterone decreases it. In ord er to measure gastric emptying, a methylcellulose test meal was given orally into the stomach of conscious rats. In progesterone-treated rat s, at the dose of 0.2 mg/kg, gastric emptying was not significantly di fferent from that of the control, but it was found to be significantly delayed at the dose of 10 mg/kg (P< 0.05). Estrogen treatment at dose s of 20 mu g/kg and 600 mu g/kg significantly delayed gastric emptying , when compared with controls (P< 0.001). Combined therapy of estrogen and progesterone induced a significant delay in gastric emptying rate compared with the control group (P< 0.001). In the animals with pseud opregnancy treatment (100 mu g/kg estrogen+ 15 mg/kg progesterone; 7-1 2 days) the gastric empying rate was significantly different from that of the control (P< 0.05). We conclude that both estrogen and progeste rone exert inhibitory effects on gastric emptying, and this may accoun t for the disturbances in gastrointestinal function that pregnant wome n frequently experience.