ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
A study was made of 174 eggs recovered from 58 guinea pigs killed between the first and sixth days after mating, and the cytological details from the stage of sperm penetration to the pre-implantation blastocyst described. Eighty-nine percent of the expected number of eggs were recovered, and 97% of these were fertilized. Embryonic development proceeded from pronuclear and 2-cell eggs on day 1 to pre-implantation blastocysts on day 6, the duration of each of the early cleavage stages being of approximately 24 hours. No progressive loss of embryos was found over this period, all the eggs recovered on days 4, 5 and 6 being regarded as developing normally. Passage of embryos from the Fallopian tubes to the uterus commenced on the afternoon of day 3, and the majority of embryos entered the uterus shortly after this time at the stage of 8- to 16-cells. The tail of the fertilizing spermatozoon was detected in the cytoplasm of all eggs examined on day 1, in most of those examined on day 2, and frequently persisted up to the 8-cell stage. Three dispermic eggs, each containing two distinct cytoplasmic sperm tails, were found: one of these was at the pronuclear stage, the other two being considered of 4- and 6-cells respectively. Properties of adhesiveness were shown by blastocysts recovered shortly before implantation on day 6, but the characteristic “zona processes” were not seen.
Additional Material:
7 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091650310
