PARTIAL PROGESTERONE DEPRIVATION ALTERS THE TRANSCRIPTION OF ESTROGEN RECEPTORS AND THEIR DOWNSTREAM GENES IN RAT PLACENTAS

Abstract

ObjectiveTo investigate the role of progesterone in placental growth and effects on the expression of estrogen receptors‐alpha and ‐beta and their downstream genes.Materials and MethodsPregnant SD rats were segregated into A) control (peanut oil, twice daily injections), B) ovariectomized on 15 day gestation (dg), with progesterone restoration, and C) progesterone reduction groups. To restore estrogen levels, estradiol was administered subcutaneously using mini‐osmotic pump (40 ng/h) and then injected to maintain normal increase in plasma levels of the hormone. In group B, progesterone level was restored by administering the hormone daily and, in group C, progesterone reduction (partial deprivation) to one third of the normally observed level of the hormone on 22 dg was maintained. Placentas were harvested on 19 dg and 21 dg and dissected into basal and labyrinth zones. Gene expression of estrogen receptors‐alpha and ‐beta, p53, Bax and Bcl‐2 was analyzed by real time‐polymerase chain reaction. Data were analyzed by one way ANOVA and Least square difference test with the level of significance set p<0.05.ResultsPartial progesterone deprivation decreased placental and basal zone weights on 19 dg (p<0.05), which was not restored by progesterone restoration to normal levels. Progesterone restoration did not recover decreased fetal body weights in overiectomized rats although placental efficiency was not affected on 21 dg. Partial progesterone deprivation increased the transcription of both estrogen receptors in the basal zone on 19 dg (p<0.05), which recovered to normal levels after progesterone restoration. Similarly, p53, Bax and Bcl‐2 gene expressions were also increased in the basal zones in partial progesterone deprived rats, which were restored to normal levels on 19 dg and 21 dg, after progesterone restoration. A similar pattern was seen in the labyrinth zone on 16 dg and 19 dg.ConclusionPartial progesterone deprivation inhibits placental and fetal growth most probably by enhancing estrogen receptor‐mediated up‐regulation of apoptosis in placentas. Progesterone is essential for normal growth of placentas and fetuses in rats.Support or Funding InformationKuwait University Research Grant # MY02/08This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.