Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jul 7, 2016; 22(25): 5761-5768
Published online Jul 7, 2016. doi: 10.3748/wjg.v22.i25.5761
Role of sex hormones in gastrointestinal motility in pregnant and non-pregnant rats
Juliana Fernandes Matos, Madileine Francely Americo, Yuri Karen Sinzato, Gustavo Tadeu Volpato, Luciana Aparecida Corá, Marcos Felipe Freitas Calabresi, Ricardo Brandt Oliveira, Debora Cristina Damasceno, Jose Ricardo Arruda Miranda
Juliana Fernandes Matos, Yuri Karen Sinzato, Debora Cristina Damasceno, Jose Ricardo Arruda Miranda, Marcos Felipe de Freitas Calabresi, Sao Paulo State University, Botucatu, SP 18618-970, Brazil
Madileine Francely Americo, Gustavo Tadeu Volpato, Instituto de Ciências Biológicas e da Saúde, Federal University of Mato Grosso, Barra do Garças, MT 78600-000, Brazil
Luciana Aparecida Corá, Universidade Estadual de Ciências da Saúde de Alagoas, Maceió, AL 57010-300, Brazil
Ricardo Brandt Oliveira, São Paulo University, Ribeirão Preto, SP 14049-900, Brazil
Author contributions: Americo MF, Sinzato YK, Damasceno DC and Miranda JRA designed the study; Matos JF and Calabresi MFF performed experiments; Americo MF, Matos JF, Calabresi MFF and Miranda JRA analyzed the data; Americo MF, Volpato GT and Oliveira RB wrote the paper; Americo MF, Sinzato YK, Volpato GT, Oliveira RB, Damasceno DC and Miranda JRA revised critically the paper; The final version of manuscript was read and approved by all authors.
Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp), No. 2010/14845-4 and No. 2015/14923-9; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), No. 150456/2009-3.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of the Bioscience Institute/UNESP Ethics Committee on Use of Animals (CEUA Process 411).
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Madileine Francely Americo, PhD, Instituto de Ciências Biológicas e da Saúde, Federal University of Mato Grosso, Avenida Valdon Varjão 6390, Barra do Garças, MT 78600-000, Brazil.
Telephone: +55-66-34015317 Fax: +55-66-34015317
Received: March 7, 2016
Peer-review started: March 8, 2016
First decision: April 14, 2016
Revised: May 7, 2016
Accepted: June 2, 2016
Article in press: June 2, 2016
Published online: July 7, 2016

AIM: To correlate gastric contractility, gastrointestinal transit, and hormone levels in non-pregnant (estrous cycle) and pregnant rats using noninvasive techniques.

METHODS: Female rats (n = 23) were randomly divided into (1) non-pregnant, (contractility, n = 6; transit, n = 6); and (2) pregnant (contractility, n = 5; transit, n = 6). In each estrous cycle phase or at 0, 7, 14, and 20 d after the confirmation of pregnancy, gastrointestinal transit was recorded by AC biosusceptometry (ACB), and gastric contractility was recorded by ACB and electromyography. After each recording, blood samples were obtained for progesterone and estradiol determination.

RESULTS: In the estrous cycle, despite fluctuations of sex hormone levels, no significant changes in gastrointestinal motility were observed. Days 7 and 14 of pregnancy were characterized by significant changes in the frequency of contractions (3.90 ± 0.42 cpm and 3.60 ± 0.36 cpm vs 4.33 ± 0.25 cpm) and gastric emptying (168 ± 17 min and 165 ± 15 min vs 113 ± 15 min) compared with day 0. On these same days, progesterone levels significantly increased compared with control (54.23 ± 15.14 ng/mL and 129.96 ± 30.52 ng/mL vs 13.25 ± 6.31 ng/mL). On day 14, we observed the highest level of progesterone and the lowest level of estradiol compared with day 0 (44.3 ± 15.18 pg/mL vs 24.96 ± 5.96 pg/mL).

CONCLUSION: Gastrointestinal motility was unaffected by the estrous cycle. In our data, high progesterone and low estradiol levels can be associated with decreased contraction frequency and slow gastric emptying.

Keywords: Reproductive physiological process, Sex hormones, Gastrointestinal motility, Magnetic fields, Gastric emptying

Core tip: In female rats, the estrous cycle and pregnancy appear to disturb gastrointestinal motility because of variations in hormone levels, although data are conflicting. In vivo gastrointestinal studies during pregnancy are limited by the lack of safe and reliable methods. AC biosusceptometry and electromyography are appropriate for recording motility while adhering to ethical standards. Sex hormone variations were not sufficient to disturb gastrointestinal motility during the estrous cycle. In our data, high progesterone and low estradiol levels can be associated with decreased contraction frequency and slow gastric emptying. These data were obtained in vivo using harmless techniques during several reproductive stages.