Effects of progesterone on gastric emptying and intestinal transit in male rats

AIM: To study the dose-dependent of progesterone (P) effect and the interaction between the oxytocin (OT) and Pon gastrointestinal motility.METHODS: In order to monitor the gastric emptying andintestinal transit, the SD male rats were intubated via acatheter with normal saline (3 mi/kg) containing Na251 CrO4(0.5 μCi/ml) and 10 % charcoal.OT was dissolved intonormal saline and P was dissolved into 75 % alcohol.RESULTS: Low does of P (1 mg/kg, i. p. ) enhanced thegastric emptying (75 ± 3 %, P＜ 0.05) and high dose of P (5mg/kg, i.p. ) inhibit it (42± 11.2 %, P＜ 0.01). P (1 rog/kg)increased the intestinal transit (4.2 ± 0. 3, P ＜ 0.05) whilethe higher dose ( 10-20 mg/kg) had no effect. OT (0.8 mg/kg, i.p. ) inhibited the gastric emptying (23.5 ± 9.8 %, P ＜0.01). The inhibitory effects of P (20 mg/kg) (32± 9.7 %, P＜ 0.05) and OT (0.8 mg/kg) on gastric emptying enhancedeach other when the two chemicals were administratedsimultaneously ( 17 ± 9.4 %, P ＜ 0.01).CONCLUSION: Low dose of P increased Gl motility whilehigh dose of P decreased it. During the later period ofpregnancy, elevated plasma level of OT may also participatein the gastrointestinal inhibition.