Progesterone receptor in Norplant endometrium

Area of Science:

• Reproductive Endocrinology
• Molecular Biology
• Gynecology

Background:

• Endometrial progesterone receptor (PR) is crucial for progestogen activity in fertility regulation.
• PR and its mRNA levels fluctuate in glandular epithelia but are stable in stromal cells during the normal menstrual cycle.
• PR mRNA and protein levels generally correlate during the normal menstrual cycle.

Purpose of the Study:

• To investigate PR and PR mRNA expression and functionality in Norplant endometrium.
• To compare PR and PR mRNA levels between Norplant users with amenorrhea and endometrial bleeding.
• To explore the relationship between PR, PR mRNA, and estrogen levels in Norplant users.

Main Methods:

• Immunohistochemistry was used to assess immunoreactive progesterone receptor concentration.
• Progesterone receptor mRNA levels were quantified.
• The expression of cathepsin D was used as a marker for functional progesterone receptor status.

Main Results:

• Norplant endometrium showed increased immunoreactive progesterone receptor but decreased progesterone receptor mRNA compared to controls.
• Functional progesterone receptor activity was not confirmed in Norplant endometrium using cathepsin D as a marker.
• Norplant subjects with amenorrhea had higher progesterone receptor mRNA and lower plasma estrogen than those with endometrial bleeding.

Conclusions:

• Glandular and stromal progesterone receptors exhibit differential sensitivity to steroid regulation during the menstrual cycle.
• A dissociation exists between progesterone receptor and its mRNA concentrations in Norplant endometrium.
• Differences in progesterone receptor mRNA and estrogen levels between amenorrheic and bleeding Norplant users warrant further investigation for clinical significance.