Med. Weter. 72 (1), 58-63, 2016
full text
| Skowronska A., Eliszewski M., Młotkowska P., Skowronski M. T. |
| Differential effects of progesterone, estradiol-17β, oxytocin, arachidonic acid, forskolin and cAMP on steroid output by the porcine uterus during implantation and placentation |
| The aim of the current study was to investigate: (1) secretion P4, E2 and A4 by whole porcine uterine explants harvested during days 14-16 of pregnancy (implantation) and days 30-32 of pregnancy (placentation); (2) whether progesterone, estradiol, and other factors: oxytocin (OT), arachidonic acid (AA; substrate for prostaglandins synthesis) as well as forskolin (FSK; adenylate cyclase activator) and cAMP (cyclic adenosine monophosphate; second messenger) regulate the release of steroid hormones within uteri during implantation and placentation. Concentrations of P4, E2 and A4 were measured in culture media by RIA. Basal uterine production of E2 after 3-h incubation was about 2-fold higher on days 30-32 compared to days 14-16 of the pregnancy. Progesterone very strongly increased secretion of E2 during the implantation and placentation after 3- and 24-h incubations. Control production of P4 by uterus explants after 3-h incubation was higher during placentation than during implantation. Estradiol consistently increased the secretion of P4 on days 14-16 and days 30-32 of the pregnancy, after 3- and 24-h incubation. The basal secretions of A4 from uterine explants after 3-h incubation in both pregnancy periods were at the same level. Progesterone stimulated A4 secretion on days 14-16 after 3- and 24-h. Estradiol also very strongly increased A4 secretion during both implantation and placentation during the incubation periods. Oxytocin did not affect the release of E2, P4 and A4 (p > 0.05) by tissue explants from either of the pregnancy periods. AA significantly stimulated E2 secretion during implantation (after 3- and 24-h incubations) and placentation (after 3-h incubation). In contrast, AA did not effect the release of P4 or A4 in either of the pregnancy periods. FSK and cAMP significantly stimulated E2 release during implantation after 3- and 24-h incubation, while during placentation only after longer incubation (24-h). The secretion of P4 was also increased by FSK during implantation after 24-h incubation and during placentation (after 3- and 24-h incubation) as well as by cAMP in both pregnancy periods after 3- and 24-h. In addition, forskolin and cAMP very strongly stimulated A4 release with uterine explants after 3- and 24-h incubation at the time of implantation and placentation. In summary, this is the first demonstration that: 1) the production and release of E2 and P4 (but not A4) from the pig uterine explants increase with advancing gestation; and 2) P4, E2, arachidonic acid, forskolin and cAMP are involved in the regulation of uterine steroidogenesis, which seems to depend on the pregnancy period and incubation time. |
| Key words: steroid hormones, uterus, pregnancy, pig |