Hamster eggs are significantly less likely to be transported through the oviduct when the eggs or the oviduct have been exposed to cigarette smoke, according to reproductive scientists at the University of California, Riverside. The result could be a disruption of fertilization and pregnancy.

The paper titled "Cigarette Smoke Inhibits Hamster Oocyte Pickup by Increasing Adhesion between the Oocyte Cumulus Complex and Oviductal Cilia," was published in the September issue of Biology of Reproduction. Authors, Prue Talbot, a professor of cell biology and graduate student Christine Gieseke, of the Department of Cell Biology and Neuroscience, reported that various types of cigarette smoke cause freshly ovulated hamster eggs, enveloped in a layer of cumulus cells, to stick to the upper part of the egg oviduct, or infundibulum. The microscopic hairs, or cilia, that transport the eggs cannot move it to where fertilization occurs.

"The results of this study show that the type of smoke inhaled by both active and passive smokers can increase adhesion between the egg and the oviduct and thereby potentially impair transfer of the egg into the oviduct where it is normally fertilized," Talbot said. "There is growing awareness that all organs are targets of cigarette smoke, and this study further supports this idea."

Gieseke and Talbot found that both the cumulus-coated eggs and the oviducts of hamsters are affected by cigarette smoke, although the oviduct experiences more adverse effects, possibly because the smoke impaired both adhesion and the tiny hair-like cilia, which move the egg into the oviduct.

When the upper region of the hamster oviduct alone was exposed to six types of cigarette smoke, eggs were 50 to 90 percent more likely to stick to the oviduct than was the case in control animals that were not exposed, and the increase in adhesion paralleled a decrease in the rate at which eggs were picked up by the oviduct.

In an accompanying comment to the paper, Biology of Reproduction co-editor Mary Ann Handel noted that the work of the UC Riverside researchers on egg transport will "open the door to future molecular analysis of this process as well as provide one more cautionary note about significant health effects of smoking."

Biology of Reproduction, published by the Society for the Study of Reproduction, is the top-rated peer-reviewed journal in the field of reproductive biology.