Investigation of effects of pregnant mare serum gonadotropin (PMSG) on the chromosomal complement of CD-1 mouse embryos.
OBJECTIVE
The objective of this study was to examine the effect of superovulatory doses of gonadotropins on the frequency of chromosomal abnormalities of mouse embryos.


METHODS
Chromosome analysis of 8- to 16-cell stage mouse embryos and zygotes was performed by a cytogenetic method.


RESULTS
There was no significant effect of the pregnant mare serum gonadotropin (PMSG) dose on the level of aneuploidy and structural abnormalities from 8- to 16-cell-stage embryos among superovulated groups. However, a simple dose-response relationship between the PMSG dose and the incidence of polyploidy was observed, with the level of polyploidy rising from 2.9% with 10 i.u. PMSG to 10.5% with 15 i.u. PMSG. In zygote stage, the proportion of polyploid embryos also increased as the dose increased, from 1.9% in 5 i.u. to 6.7% in 15 i.u. PMSG. It was observed that the extra chromosomal set in polyploidy embryos originated by both fertilization of a diploid oocyte and dispermy.


CONCLUSIONS
These results indicate a dose-response relationship between the PMSG dose and the incidence of polyploidy in the CD-1 mouse. Both a disturbance at maturation division and an error at fertilization were the cause of polyploidy.
Ma
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Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, Canada.
Kalousek
D K
DK
Yuen
B H
BH
Moon
Y S
YS
D000782:Aneuploidy; D000818:Animals; D002869:Chromosome Aberrations; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian / Q000187:drug effects / Q000502:physiology*; D005314:Embryonic and Fetal Development; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D010060:Ovulation / Q000187:drug effects; D011247:Pregnancy; D015053:Zygote
D006064:Gonadotropins, Equine