Abstract
Eggs derived from superovulated F1(BALB/c × C57BL/6) mice were fertilized in a modified Krebs-Ringer bicarbonate medium (TYH) containing 2-mM caffeine. Spermatozoa obtained from the cauda epididymis of ICR male mice were preincubated in the caffeine-containing for 2 h before the mixing of gametes. Gametes preincubated and inseminated in the caffeine-free medium served as controls. Chromosome analysis at the first cleavage showed a significantly (P<0.05) higher incidence of triploidy in eggs fertilized in the caffeine-containing medium (22.9%) than in the control (15.8%). The incidence of aneuploidy and the sex ratio were not significantly different between the two groups of eggs. Most of the triploid eggs observed were considered to be dispermic in origin.
