Effects of injecting calcium chloride into in vitro-matured porcine oocytes.
In vitro-matured porcine oocytes were given injections of 0.1 M CaCl2 and after 6 h evaluated for signs of early and late activation events. CaCl2 injection caused cortical granule exocytosis in 75% (3 of 4) of the oocytes tested. It also induced cell cycle resumption as monitored by the histone H1 kinase assay: the phosphorylation rate of histone H1 decreased to 36.7% of the original value. Treated oocytes completed meiosis, extruded the second polar body, and progressed to first interphase: 79.4% of them formed one or more pronuclei. The elevated intracellular Ca2+ level resulted in activation-related changes in the protein synthetic profile in 90% (9 of 10) of the oocytes. Furthermore, 14.7% (9 of 61) of the treated oocytes developed to the compact morula/early blastocyst stage after a 7-day culture in ligated porcine oviduct, and one blastocyst hatched from the zona pellucida. Control oocytes given injections of 0.1 M MgCl2 or carrier medium (10 mM Hepes) did not show the changes mentioned. The results strengthen the idea that Ca2+ is a cell messenger that plays a central part in oocyte activation; it is concluded that elevated intracellular Ca2+ level caused by a single injection of CaCl2 leads to both early and late events of porcine oocyte activation.
Macháty
Z
Z
Department of Animal Sciences, University of Missouri-Columbia 65211, USA.
Funahashi
H
H
Mayes
M A
MA
Day
B N
BN
Prather
R S
RS
D000818:Animals; D001755:Blastocyst; D002122:Calcium Chloride / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D003594:Cytoplasmic Granules / Q000187:drug effects; D005089:Exocytosis / Q000187:drug effects; D005260:Female; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D016200:Maturation-Promoting Factor / Q000378:metabolism; D008540:Meiosis / Q000187:drug effects; D009028:Morula; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D013552:Swine
D015636:Magnesium Chloride; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D016200:Maturation-Promoting Factor; D002122:Calcium Chloride