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Tissue- and hormone-dependent progesterone receptor distribution in the rat uterus.

Sahlin L, Masironi B, Akerberg S, Eriksson H - Reprod. Biol. Endocrinol. (2006)

Bottom Line: These results suggest that ERbeta signals mainly down-regulate PR levels in the epithelial cells.ERalpha, on the other hand, up-regulates PR levels in the stroma and myometrium while it decreased them in LE.Thus, the effects from E2 and PPT on the mRNA levels, as determined by PCR, could be annihilated since they are increased and decreased depending on cell type.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division for Reproductive Endocrinology, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden. lena.sahlin@ki.se

ABSTRACT

Background: Estradiol (E2) and progesterone (P) are well known regulators of progesterone receptor (PR) expression in the rat uterus. However, it is not known which receptor subtypes are involved. Little knowledge exist about possible differences in PR regulation through ERalpha or ERbeta, and whether the PR subtypes are differently regulated depending on ER type bound. Thus, in the present study PR immunostaining has been examined in uteri of ovariectomized (ovx) rats after different treatments of estrogen and P, in comparison with that in immature, cycling, and pregnant animals.

Methods: The uteri were collected from 1) ovx rats treated with E2 and/or P; 2) immature rats, intact cycling rats and animals pregnant day 8 and 18; 3) ovx rats treated with E2 or an estrogen receptor (ER)alpha agonist or an ERbeta agonist. Two antibodies were used, one detecting PRA+B and another one specific for PRB. Real-time PCR was used to determine mRNA levels for PRAB and PRB in experiment 3.

Results: In stroma and myometrium faint staining was detected in ovx controls (OvxC), whereas E2 treatment resulted in strong staining. In contrast to this, in luminal epithelium (LE) the staining was strong in the OvxC group, whereas E2 treatment during the last 24 hrs before sacrifice caused a decrease. Similar to OvxC the LE of the immature animals was strongly stained. In the pregnant rats LE was negative, well in agreement with the results seen after E2 treatment. In the pregnant animals the stroma and decidua was strongly stained for PRAB, but only faint for PRB, indicating that PRA is the most expressed isoform in this state. The increase in stromal and myometrial immunostaining after E2 treatment was also found after treatment with the ERalpha agonist PPT. The ERbeta agonist DPN caused a decrease of the PR mRNA levels, which was also found for PRAB and PRB immunostaining in the GE.

Conclusion: Stromal and myometrial PRAB levels are increased via ERalpha, as shown by treatment with E2 and the ERalpha agonist PPT, while the levels in LE are decreased. The uterine stroma of pregnant rats strongly expressed PRAB, but very little PRB, which is different to E2 treated ovx animals where both PRAB and PRB are strongly expressed. The ERbeta agonist DPN decreased the mRNA levels of PRAB and PRB, as well as the PRAB protein level in GE. These results suggest that ERbeta signals mainly down-regulate PR levels in the epithelial cells. ERalpha, on the other hand, up-regulates PR levels in the stroma and myometrium while it decreased them in LE. Thus, the effects from E2 and PPT on the mRNA levels, as determined by PCR, could be annihilated since they are increased and decreased depending on cell type. The distribution and amount of PR isoforms strongly depend on the hormonal milieu and cell type within the rat uterus.

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Scoring results PRB experiment 1. Results from manual scoring of PRB immunohistochemistry results in stroma (upper panel), luminal epithelium (LE, middle panel) and myometrium (bottom panel). The "box-and-whisker plot" represents the median value with 50% of all data falling within the box. The whiskers extend to the 5th and 95th percentiles. An asterisk indicates a significant (p < 0.05) difference compared to the OvxC group.
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Figure 3: Scoring results PRB experiment 1. Results from manual scoring of PRB immunohistochemistry results in stroma (upper panel), luminal epithelium (LE, middle panel) and myometrium (bottom panel). The "box-and-whisker plot" represents the median value with 50% of all data falling within the box. The whiskers extend to the 5th and 95th percentiles. An asterisk indicates a significant (p < 0.05) difference compared to the OvxC group.

Mentions: PRB. There was faint staining in the uterine stroma of the OvxC group (Fig 1I), but E2 treatment the last 24 hrs before sacrifice resulted in strong staining (Fig. 3, top panel; Fig 1J,L,O). P treatment the last 24 hrs before sacrifice showed an intermediary type of staining, but it was not different from either OvxC or the E2 treated animals (Fig 3, top panel; Fig. 1K,M,N). The PRB immunostaining in the LE of the OvxC group was very strong (Fig 1I), but was decreased in the groups that received E2 the last 24 hrs before sacrifice (Fig 3, middle panel; Fig 1J,L,O). The 24P and 48P groups showed a similar strong staining as the controls (Fig 1K,M), whereas the 24E+24P group showed an intermediary type of staining (Fig 1N), not significantly different from either OvxC or E2 treated groups (Fig 3, middle panel). There was very faint staining in the myometrium of the OvxC group (Fig 3, bottom panel, Fig 1I). E2 treatment during the last 24 hrs prior to sacrifice resulted in very strong immunostaining of the myometrium (Fig 3, bottom panel; Fig 1J,L,O). In the GE none of the treatment groups were different to the OvxC group (data not shown). Normal mouse IgG replaced the primary antibodies to obtain negative controls for the immunohistochemistry assays, the result was completely negative (Fig 1H).


Tissue- and hormone-dependent progesterone receptor distribution in the rat uterus.

Sahlin L, Masironi B, Akerberg S, Eriksson H - Reprod. Biol. Endocrinol. (2006)

Scoring results PRB experiment 1. Results from manual scoring of PRB immunohistochemistry results in stroma (upper panel), luminal epithelium (LE, middle panel) and myometrium (bottom panel). The "box-and-whisker plot" represents the median value with 50% of all data falling within the box. The whiskers extend to the 5th and 95th percentiles. An asterisk indicates a significant (p < 0.05) difference compared to the OvxC group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1586009&req=5

Figure 3: Scoring results PRB experiment 1. Results from manual scoring of PRB immunohistochemistry results in stroma (upper panel), luminal epithelium (LE, middle panel) and myometrium (bottom panel). The "box-and-whisker plot" represents the median value with 50% of all data falling within the box. The whiskers extend to the 5th and 95th percentiles. An asterisk indicates a significant (p < 0.05) difference compared to the OvxC group.
Mentions: PRB. There was faint staining in the uterine stroma of the OvxC group (Fig 1I), but E2 treatment the last 24 hrs before sacrifice resulted in strong staining (Fig. 3, top panel; Fig 1J,L,O). P treatment the last 24 hrs before sacrifice showed an intermediary type of staining, but it was not different from either OvxC or the E2 treated animals (Fig 3, top panel; Fig. 1K,M,N). The PRB immunostaining in the LE of the OvxC group was very strong (Fig 1I), but was decreased in the groups that received E2 the last 24 hrs before sacrifice (Fig 3, middle panel; Fig 1J,L,O). The 24P and 48P groups showed a similar strong staining as the controls (Fig 1K,M), whereas the 24E+24P group showed an intermediary type of staining (Fig 1N), not significantly different from either OvxC or E2 treated groups (Fig 3, middle panel). There was very faint staining in the myometrium of the OvxC group (Fig 3, bottom panel, Fig 1I). E2 treatment during the last 24 hrs prior to sacrifice resulted in very strong immunostaining of the myometrium (Fig 3, bottom panel; Fig 1J,L,O). In the GE none of the treatment groups were different to the OvxC group (data not shown). Normal mouse IgG replaced the primary antibodies to obtain negative controls for the immunohistochemistry assays, the result was completely negative (Fig 1H).

Bottom Line: These results suggest that ERbeta signals mainly down-regulate PR levels in the epithelial cells.ERalpha, on the other hand, up-regulates PR levels in the stroma and myometrium while it decreased them in LE.Thus, the effects from E2 and PPT on the mRNA levels, as determined by PCR, could be annihilated since they are increased and decreased depending on cell type.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division for Reproductive Endocrinology, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden. lena.sahlin@ki.se

ABSTRACT

Background: Estradiol (E2) and progesterone (P) are well known regulators of progesterone receptor (PR) expression in the rat uterus. However, it is not known which receptor subtypes are involved. Little knowledge exist about possible differences in PR regulation through ERalpha or ERbeta, and whether the PR subtypes are differently regulated depending on ER type bound. Thus, in the present study PR immunostaining has been examined in uteri of ovariectomized (ovx) rats after different treatments of estrogen and P, in comparison with that in immature, cycling, and pregnant animals.

Methods: The uteri were collected from 1) ovx rats treated with E2 and/or P; 2) immature rats, intact cycling rats and animals pregnant day 8 and 18; 3) ovx rats treated with E2 or an estrogen receptor (ER)alpha agonist or an ERbeta agonist. Two antibodies were used, one detecting PRA+B and another one specific for PRB. Real-time PCR was used to determine mRNA levels for PRAB and PRB in experiment 3.

Results: In stroma and myometrium faint staining was detected in ovx controls (OvxC), whereas E2 treatment resulted in strong staining. In contrast to this, in luminal epithelium (LE) the staining was strong in the OvxC group, whereas E2 treatment during the last 24 hrs before sacrifice caused a decrease. Similar to OvxC the LE of the immature animals was strongly stained. In the pregnant rats LE was negative, well in agreement with the results seen after E2 treatment. In the pregnant animals the stroma and decidua was strongly stained for PRAB, but only faint for PRB, indicating that PRA is the most expressed isoform in this state. The increase in stromal and myometrial immunostaining after E2 treatment was also found after treatment with the ERalpha agonist PPT. The ERbeta agonist DPN caused a decrease of the PR mRNA levels, which was also found for PRAB and PRB immunostaining in the GE.

Conclusion: Stromal and myometrial PRAB levels are increased via ERalpha, as shown by treatment with E2 and the ERalpha agonist PPT, while the levels in LE are decreased. The uterine stroma of pregnant rats strongly expressed PRAB, but very little PRB, which is different to E2 treated ovx animals where both PRAB and PRB are strongly expressed. The ERbeta agonist DPN decreased the mRNA levels of PRAB and PRB, as well as the PRAB protein level in GE. These results suggest that ERbeta signals mainly down-regulate PR levels in the epithelial cells. ERalpha, on the other hand, up-regulates PR levels in the stroma and myometrium while it decreased them in LE. Thus, the effects from E2 and PPT on the mRNA levels, as determined by PCR, could be annihilated since they are increased and decreased depending on cell type. The distribution and amount of PR isoforms strongly depend on the hormonal milieu and cell type within the rat uterus.

Show MeSH
Related in: MedlinePlus