title: Progesterone, estradiol, arachidonic acid, oxytocin, forskolin and cAMP influence on aquaporin 1 and 5 expression in porcine uterine explants during the mid-luteal phase of the estrous cycle and luteolysis: an in vitro study.
abstract: BACKGROUND
  The cell membrane water channel protein, aquaporins (AQPs), regulate cellular water transport and cell volume and play a key role in water homeostasis. Recently, AQPs are considered as important players in the field of reproduction. In previous studies, we have established the presence of AQP1 and 5 in porcine uterus. Their expression at protein level altered in distinct tissues of the female reproductive system depending on the phase of the estrous cycle. However, the regulation of aquaporin genes and proteins expression has not been examined in porcine uterine tissue. Therefore, we have designed an in vitro experiment to explain whether steroid hormones, progesterone (P4) and estradiol (E2), and other factors: oxytocine (OT), arachidonic acid (AA; substrate for prostaglandins synthesis) as well as forskolin (FSK; adenylate cyclase activator) and cAMP (second messenger, cyclic adenosine monophosphate) may impact AQPs expression.
  
  
  METHODS
  Uterine tissues were collected on Days 10-12 and 14-16 of the estrous cycle representing the mid-luteal phase and luteolysis. Real-time PCR and Western blot analysis were performed to examine the expression of porcine AQP1 and AQP5. Their expression in the uterine explants was also evaluated by immunohistochemistry.
  
  
  RESULTS
  The results indicated that uterine expression of AQP1 and AQP5 potentially remains under control of steroid hormones and AA-derived compounds (e.g. prostaglandins). P4, E2, AA, FSK and cAMP cause translocation of AQP5 from apical to the basolateral plasma membrane of the epithelial cells, which might affect the transcellular water movement (through epithelial cells) between uterine lumen and blood vessels. The AC/cAMP pathway is involved in the intracellular signals transduction connected with the regulation of AQPs expression in the pig uterus.
  
  
  CONCLUSIONS
  This study documented specific patterns of AQP1 and AQP5 expression in response to P4, E2, AA, FSK and cAMP, thereby providing new indirect evidence of their role in maintaining the local fluid balance within the uterus during the mid-luteal phase of the estrous cycle and luteolysis in pigs.
authors.affiliation: Department of Human Physiology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland. agnieszka.skowronska@uwm.edu.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Skowronska
authors.affiliation: Department of Animal Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland. patrycja.mlotkowska@wp.pl.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Młotkowska
authors.affiliation: Department of Animal Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland. bartosz.wojciechowicz@uwm.edu.pl.
authors.forename: Bartosz
authors.initials: B
authors.lastname: Wojciechowicz
authors.affiliation: Department of Animal Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland. stanislaw.okrasa@uwm.edu.pl.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Okrasa
authors.affiliation: Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark. sn@hst.aau.dk.
authors.forename: Soren
authors.initials: S
authors.lastname: Nielsen
authors.affiliation: Department of Animal Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland. skowron@uwm.edu.pl.|Institute of Veterinary, Poznań University of Life Sciences, Poznań, Poland. skowron@uwm.edu.pl.
authors.forename: Mariusz T
authors.initials: MT
authors.lastname: Skowronski
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000235:genetics / Q000378:metabolism; D051402:Aquaporin 5 / Q000235:genetics / Q000378:metabolism; D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D016718:Arachidonic Acid / Q000494:pharmacology*; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000494:pharmacology*; D004958:Estradiol / Q000494:pharmacology; D030762:Estrous Cycle / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D066298:In Vitro Techniques; D008183:Luteal Phase / Q000235:genetics / Q000378:metabolism; D003341:Luteolysis / Q000235:genetics / Q000378:metabolism; D010121:Oxytocin / Q000494:pharmacology*; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger; D013552:Swine / Q000378:metabolism*; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism
chemical_list: D051402:Aquaporin 5; D020346:Aquaporins; D012739:Gonadal Steroid Hormones; D012333:RNA, Messenger; D051398:Aquaporin 1; D005576:Colforsin; D016718:Arachidonic Acid; D011374:Progesterone; D004958:Estradiol; D010121:Oxytocin; D000242:Cyclic AMP