Further indications of the multicomponent nature of the acrosome reaction-inducing substance of human follicular fluid

✍ Scribed by Petra Fehl; Werner Miska; Ralf Henkel

• Book ID: 102952739
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 888 KB
• Volume: 42
• Category: Article
• ISSN: 1040-452X
• DOI: 10.1002/mrd.1080420111

✦ Synopsis

Abstract

Human follicular fluid (hFF), which has been treated with either unspecific proteases or dextran‐coated charcoal (DCC) to remove proteins and/or steroids, cannot successfully induce the acrosome reaction (AR). After the removal of steroids, AR‐inducing activity can be restored to hFF by supplementation with exogenous progesterone, but only in the presence of intact protein. Gel filtration experiments with ^3^H‐progesterone‐labelled hFF showed elution of the radioactive signal in the high molecular weight range, corresponding to bound progesterone. AR‐inducing activity was seen in exactly the same fraction. Based on these results, the acrosome reaction‐inducing substance (ARIS) appears to be a complex of progesterone and a progesterone‐binding protein, which was shown to be identical with the plasma protein corticosteroid‐binding globulin (CBG) by immunological techniques. AR induction was only observed in the presence of both CBG and progesterone, suggesting a combined effect of the two components. © 1995 wiley‐Liss, Inc.