Effect of Gonadal Hormones on Colonic Contractile Activity in Albino Rats

Abstract

Sex differences were reported in Irritable Bowel Syndrome. We aimed to demonstrate the effect of gonadal hormones on colonic contractile activity. In this study, we performed in vitro measurements of colonic contractile activity in longitudinal smooth muscle strips of female and male Albino rats. After administration of a gonadal hormone (estrogen (EST), progesterone (PROG) and testosterone (TEST)) or ethanol (ETH) solution as control, stimulation with acetylcholine (ACh) or inhibition with norepinephrine (NE) was performed. We found that increasing doses of EST resulted in a stepwise inhibition of SCCA in both sexes and inhibited the ACh effect in females. Similarly, high dose PROG inhibited SCCA in females. TEST inhibited SCCA in males but not Ach induced contractions. TEST reduced the inhibitory effect of NE in female rats. In conclusion, exposure of colonic smooth muscle strips to gonadal hormones led to sex-dependent changes in SCCA and modified the response of smooth muscle strips to both pro-contractile and anti-contractile neurotransmitters.