title: Injection of sperm heads into immature rat oocytes.
abstract: When sperm heads are injected into rat oocytes at the germinal vesicle stage the sperm heads remain intact until the germinal vesicle breaks down. Then they decondense but do not form pronuclei. This observation agrees with the results reported for in vitro fertilization of immature oocytes from rats, mice and hamsters.
mesh_terms: D000818:Animals; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000379:methods; D008297:Male; D051379:Mice; D008846:Micromanipulation; D009865:Oocytes / Q000502:physiology*; D009866:Oogenesis; D010063:Ovum / Q000502:physiology*; D051381:Rats; D013077:Sperm Head / Q000502:physiology*; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000502:physiology*