title: Does phospholipase C inhibit fusion between hamster sperm and zona-free eggs?
abstract: Previous studies (Hirao and Yanagimachi: Gamete Res. 1:3-12, 1978) have found that phospholipase C (PLC) preparations inhibit sperm-egg fusion. We have attempted to duplicate these results with PLC, as well as with a more specific enzyme, phosphatidylinositol-specific PLC. PLC preparations were applied externally to zona-free hamster eggs prior to incubation with sperm. Phosphatidylinositol-specific PLC did not inhibit sperm penetration. The degree of sperm-egg fusion observed after egg exposure to PLC, however, was dependent upon the purity of the commercial preparation. An impure sample of PLC inhibited sperm penetration, while a more purified preparation did not. The morphology of eggs was unaffected by exposure to phosphatidylinositol-specific PLC and the more purified PLC preparation. The impure preparation, however, was disruptive primarily to the egg plasma membrane as well as to internal organelle organization. The degree of damage by the impure PLC preparation was concentration dependent. The results suggest that as purity of the PLC preparation is increased, the adverse effects of PLC on sperm-egg fusion become negligible.
authors.affiliation: Department of Biological Structure, School of Medicine, University of Washington, Seattle 98195.
authors.forename: J M
authors.initials: JM
authors.lastname: Clark
authors.forename: J K
authors.initials: JK
authors.lastname: Koehler
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D006224:Cricetinae; D004340:Drug Contamination; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005456:Fluorescent Dyes; D005614:Freeze Fracturing; D008297:Male; D008647:Mesocricetus; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism; D010063:Ovum / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D020112:Rhodamine 123; D012235:Rhodamines / Q000378:metabolism; D013084:Sperm-Ovum Interactions / Q000187:drug effects*; D010738:Type C Phospholipases / Q000302:isolation & purification / Q000494:pharmacology* / Q000592:standards; D015044:Zona Pellucida / Q000502:physiology
chemical_list: D005456:Fluorescent Dyes; D012235:Rhodamines; D020112:Rhodamine 123; D010738:Type C Phospholipases