Human oocyte derived sperm chemoattractant is a hydrophobic molecule associated with a carrier protein

Capsule:
Treating oocyte-conditioned media with proteases and hexane provided evidence for the oocyte derived chemoattractant being a hydrophobic nonpeptide molecule that, in an oocyte-conditioned medium, is associated with a carrier protein.

Authors:
Leah Armon, Ph.D., Ido Ben‐Ami, M.D., Ph.D., Raphael Ron-El, M.D., Michael Eisenbach, Ph.D.

Volume 102, Issue 3, Pages 885-890

Abstract:

Objective:
To characterize the nature of the human oocyte-derived chemoattractant.

Design:
Laboratory in vitro study.

Setting:
Academic research institute.

Patient(s):
Ten healthy sperm donors. Oocyte-conditioned media from women undergoing IVF treatment because of male factor infertility.

Intervention(s):
Sperm samples were processed by the migration-sedimentation technique. Oocyte-conditioned media were collected 2–3 hours after oocyte stripping.

Main Outcome Measure(s):
Sperm chemotaxis was assayed in a μ-slide chamber according to the direction of swimming relative to that of the chemical gradient.

Result(s):
Oocyte-conditioned media treated with proteases did not lose their chemotactic activity; on the contrary, they became more active, with the activity shifted to lower concentrations. When oocyte-conditioned media were subjected to hexane extraction, chemotactic activity was found in both the hydrophobic and aqueous phases. Known mammalian sperm chemoattractants were ruled out as oocyte-derived chemoattractants.

Conclusion(s):
Our results suggest that the oocyte-derived chemoattractant is a hydrophobic nonpeptide molecule that, in an oocyte-conditioned medium, is associated with a carrier protein that enables its presence in a hydrophilic environment.

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