Transient expression of progesterone receptor and cathepsin-l in human granulosa cells during the periovulatory period

Capsule:
Human chorionic gonadotropin/luteinizing hormone modulates progesterone receptor and cathepsin-L expression in human preovulatory granulosa cells, suggesting that both peptides are critical in human ovulation.

Authors:
Víctor García, M.D., Ph.D., Paulina Kohen, B.S., Carola Maldonado, Ph.D., Walter Sierralta, Ph.D., Alex Muñoz, B.S., Claudio Villarroel, M.D., Jerome F. Strauss III, M.D., Ph.D., Luigi Devoto, M.D.
Volume 97, Issue 3 , Pages 707-713.e1, March 2012

Objective:
To study in vivo the progesterone receptor (PR) expression levels in human granulosa cells (GCs) during the periovulatory period and the affect of the protein kinase A (PKA) pathway on PR expression and cathepsin-L expression-activation.

Design:
Experimental study.

Setting:
University research unit.

Patient(s):
Twenty-five women of reproductive age.

Intervention(s):
Follicular fluid and GCs obtained from spontaneous cycles before and during the normal luteinizing hormone surge, and samples obtained 36 hours after human chorionic gonadotropin (hCG) administration in patients undergoing in vitro fertilization.

Main Outcome Measure(s):
To determine PR, cathepsin-L messenger RNA (mRNA) analysis via real-time polymerase chain reaction, and protein of PR, cathepsin-L, and PKA in human GCs.

Result(s):
The Western blot analysis revealed that bands of PR (isoform A) were the most abundant and that mRNA (PR-A and PR-B) have a temporal pattern of expression throughout the periovulatory period. The protein levels of PR and cathepsin-L were up-regulated by hCG. The abundance of PR was diminished in the presence of PKA inhibitor, and cathepsin-L with PR receptor antagonist.

Conclusion(s):
The transient expression of PR in human GCs of the preovulatory follicle suggests that PR and its ligand play a role in the activation of cathepsin-L, which is presumably involved in the degradation of the follicular extracellular matrix during human ovulation.

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