Effect of Ovariectomy on Egg Transport in the Rabbit

• Published in: Biology of reproduction Vol. 16; no. 3; pp. 397 - 402
• Main Authors: Spilman, C H, Beauving, D C
• Format: Journal Article
• Language: English
• Published: United States Society for the Study of Reproduction 01-04-1977
• Subjects: Animals; Castration; Chorionic Gonadotropin - pharmacology; Estradiol - metabolism; Estrogens - pharmacology; Estrus; Fallopian Tubes - metabolism; Female; Ovary - metabolism; Ovulation - drug effects; Ovum Transport - drug effects; Population; Pregnancy; Progestins - metabolism; Prostaglandins F - metabolism; Rabbits; Time Factors; Genitalia; Ovum Transport; Ovariectomy; Gonadotropins, Chorionic; Biology; Urogenital Surgery; Germ Cells; Research Methodology; Gynecologic Surgery; Ovulation; Urogenital System; Reproduction; Treatment; Clinical Research; Surgery; Ovum; Physiology; Animals, Laboratory
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod16.3.397

The importance of pre- and postovulatory ovarian steroid secretion on egg transport through
the entire oviduct was studied in the rabbit. Estrous New Zealand rabbits were induced to ovulate
with human chorionic gonadotropin (hCG), had eggs transferred to the oviducts, were bilaterally
ovariectomized and had eggs transferred to the oviducts, or were induced to ovulate with hCG and
were bilaterally ovariectomized shortly after ovulation. Groups of animals so treated were
sacrificed at either 48 h or 72 h after ovulation or egg transfer. The oviductal recovery of eggs and
the distance traveled by the eggs was determined. Eggs transferred to the oviducts of estrous
rabbits were transported rapidly; only 15.9 ± 9.7 percent of the eggs could be recovered from the
oviducts of estrous rabbits 48 h after transfer. In contrast, between 72 percent and 86 percent of
the eggs were still located in the oviducts in the other groups sacrificed at a similar time. By 72 h
after egg transfer or ovulation no eggs could be found in the oviducts of estrous rabbits, and only
8.6 ± 4.8 percent of the eggs were located in the oviducts of rabbits induced to ovulate with hCG.
However, if estrous rabbits were bilaterally ovariectomized immediately before egg transfer or were
ovariectomized shortly after hCG-induced ovulation approximately 40 percent of the eggs were still
located in the oviducts at 72 h. The results demonstrate that egg transport through the entire
oviduct is fastest in estrous rabbits, and that acute steroid withdrawal (ovariectomy) and normal
preovulatory steroid changes act to impede egg transport rates. However, steroid withdrawal by
itself is not sufficient to cause normal egg transport. It appears that preovulatory steroid surges are
important for subsequent normal egg transport. When rabbits were ovariectomized shortly after
ovulation egg transport was delayed. The data suggest that preovulatory steroid surges and/or
steroid withdrawal induce an impeding effect on egg transport, and that postovulatory steroid
secretion changes are essential to overcome this impeding effect and facilitate normal egg transport
through the entire oviduct.