title: Progesterone, estrogen and pregnancy do not decrease colon myoelectric activity in rats: an in vivo study.
abstract: BACKGROUND
  Progesterone, estrogen and the hormonal complex of pregnancy have been responsible for some degree of colon hypomotility in human pregnancy.
  
  
  OBJECTIVE
  To find out if estrogen, progesterone and the hormonal complex of pregnancy decrease colon myoelectric activity.
  
  
  METHODS
  The study was performed in 37 healthy female rats in which electrodes were implanted on the serosa of the proximal ascendent, distal ascendent, transverse, and descendent colon. We analyzed the records of colon myoelectric activity in vivo in five groups: control, ovariectomized, ovariectomized and treated with estrogen, ovariectomized and treated with progesterone, and pregnant rats.
  
  
  RESULTS
  We found a great variation in myoelectric activity in all groups studied. The mean of electric activity did not show statistical difference among the five groups, but pregnant rats had a statistically significant higher duration of maximum electric activity in all distances from the cecocolon junction.
  
  
  CONCLUSIONS
  Pregnant rats had a statistically higher duration of maximum electric activity. If we could transpose these results to humans, this increase in duration of colon myoelectric activity could explain, in part, the slight constipation that some pregnant women have.
authors.affiliation: Laboratory of Clinical Investigation LIM 07, Department of Gastroenterology, University of São Paulo School of Medicine, São Paulo, Brazil. manlio.sp@uol.com.br
authors.forename: L B M
authors.initials: LB
authors.lastname: Speranzini
authors.forename: P P
authors.initials: PP
authors.lastname: Lopasso
authors.forename: A A
authors.initials: AA
authors.lastname: Laudanna
mesh_terms: D000818:Animals; D003106:Colon / Q000502:physiology*; D004967:Estrogens / Q000502:physiology*; D005260:Female; D023421:Models, Animal; D016065:Myoelectric Complex, Migrating / Q000502:physiology*; D011247:Pregnancy / Q000502:physiology*; D011374:Progesterone / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004967:Estrogens; D011374:Progesterone