Effects of progesterone on gastric emptying and intestinal transit in male rats.
OBJECTIVE
To study the dose-dependent of progesterone (P) effect and the interaction between the oxytocin (OT) and P on gastrointestinal motility.


METHODS
In order to monitor the gastric emptying and intestinal transit, the SD male rats were intubated via a catheter with normal saline (3 ml/kg) containing Na(2)(51)CrO(4) (0.5 microCi/ml) and 10% charcoal. OT was dissolved into normal saline and P was dissolved into 75% alcohol.


RESULTS
Low does of P (1 mg/kg, i.p.) enhanced the gastric emptying (75+/-3%, P<0.05) and high dose of P (5 mg/kg, i.p.) inhibit it (42+/-11.2%, P<0.01). P (1 mg/kg) increased the intestinal transit (4.2+/-0.3, P<0.05) while the 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 enhanced each other when the two chemicals were administrated simultaneously (17+/-9.4%, P<0.01).


CONCLUSIONS
Low dose of P increased GI motility while high dose of P decreased it. During the later period of pregnancy, elevated plasma level of OT may also participate in the gastrointestinal inhibition.
Liu
Chuan-Yong
CY
Department of Physiology, School of Medicine, Shandong University, Jinan 250012, Shandong Province, China. liucy@sdu.edu.cn
Chen
Lian-Bi
LB
Liu
Pei-Yi
PY
Xie
Dong-Ping
DP
Wang
Paulus S
PS
D000818:Animals; D004347:Drug Interactions; D005746:Gastric Emptying / Q000187:drug effects*; D005772:Gastrointestinal Transit / Q000187:drug effects*; D008297:Male; D010121:Oxytocin / Q000494:pharmacology*; D011374:Progesterone / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D011374:Progesterone; D010121:Oxytocin