Inhibitory effect of glucose and phosphate on the second cleavage division of hamster embryos: is it linked to metabolism?
Hamster embryos cannot complete the second cleavage division in vitro in the presence of glucose and inorganic phosphate (Glu/Pi). Embryos can recover from an 8 h (12:30-20:30 h) exposure to Glu/Pi, although cleavage is retarded by 10 h and continued development to the blastocyst stage is rare (2%). The vulnerability of 2-cell embryos to Glu/Pi changes during the cell cycle, being greatest just prior to cleavage which occurs at approximately 21:00 h: exposure to Glu/Pi from 12:30-14:30 h allowed 94% development to morulae/blastocysts while exposure from 18:30-20:30 h decreased morula/blastocyst development to 48%. This inhibitory effect is also modulated by the length of exposure and energy substrate composition of the culture medium. It is unclear how Glu/Pi interferes with cleavage, but a metabolic explanation is likely because (i) metabolic inhibitors L-glyceraldehyde, iodoacetate and cystamine exacerbated the effect and (ii) the organization of active mitochondria observed with Rhodamine 123 and confocal microscopy is disturbed by Glu/Pi.
Barnett
D K
DK
Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, 1655 Linden Drive, Madison, WI 53706, USA.
Bavister
B D
BD
D000818:Animals; D001755:Blastocyst / Q000187:drug effects; D002970:Cleavage Stage, Ovum / Q000187:drug effects*; D006224:Cricetinae; D003470:Culture Media; D003538:Cystamine / Q000494:pharmacology; D004622:Embryo, Mammalian / Q000648:ultrastructure; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D005985:Glyceraldehyde / Q000494:pharmacology; D006019:Glycolysis / Q000187:drug effects; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D008928:Mitochondria / Q000187:drug effects / Q000648:ultrastructure; D009028:Morula / Q000187:drug effects; D010710:Phosphates / Q000494:pharmacology*; D013997:Time Factors
D003470:Culture Media; D007461:Iodoacetates; D010710:Phosphates; D005985:Glyceraldehyde; D005947:Glucose; D003538:Cystamine; D019807:Iodoacetic Acid