Progesterone receptors: various forms and functions in reproductive tissues

Area of Science:

• Reproductive biology
• Endocrinology
• Molecular genetics

Background:

• Progesterone is vital for female reproduction, including ovulation and pregnancy.
• Progesterone receptors (PR-A and PR-B) mediate progesterone's actions as transcriptional factors.
• Emerging evidence suggests progesterone's role in male reproductive events.

Purpose of the Study:

• To review the forms and functions of progesterone receptors (PR) in various reproductive tissues.
• To highlight the distinct characteristics and localization of PR in human spermatozoa.
• To discuss the potential of PR as a biomarker for sperm fertilizing potential.

Main Methods:

• Literature review of studies on progesterone receptor expression and function.
• Analysis of data on PR localization in spermatozoa and testis.
• Correlation of PR levels in spermatozoa with male fertility status.

Main Results:

• Progesterone receptor (PR) is present in human spermatozoa, localized on the membrane with distinct characteristics.
• Inhibition of sperm membrane PR impairs progesterone-driven functions like motility and acrosome reaction.
• Lower percentages of PR-positive spermatozoa are observed in infertile men compared to fertile men.
• PR is confirmed as an inherent testicular protein, not secreted by accessory organs.

Conclusions:

• Sperm membrane PR plays a critical role in sperm function and fertilizing capacity.
• PR levels in spermatozoa may serve as a reliable marker for assessing male fertility potential.
• This review consolidates current knowledge on PR forms across reproductive tissues, emphasizing its significance in male reproduction.