Effects of exogenous GnRH administration on serum estradiol 17 beta levels and cytological changes in vaginal epithelium in bitches

Abstract

The aim of this study is to demonstrate the changes in serum estradiol 17 beta levels and vaginal epithelium after the administration of exogenous GnRH as well as to determine whether this data can be used to diagnose ovarian remnant syndrome, inactive ovarium or bitches with obscure history of previous spaying. Thirty-nine bitches of various breeds have been included in the study. Twenty bitches with no history of spaying and which were proved not to be in proestrus or estrus according to anamnesis and vaginal cytological examination constituted Group I, while Group II consisted of 19 bitches which were formerly spayed. GnRH administration was performed to confirm the presence of ovarian tissue in the bitches in Groups I and II. Blood samples were taken from both groups to assess the changes in blood estradiol 17 beta levels both prior to and 75 minutes after GnRH administration. Bitches in both groups also underwent simultaneous vaginal examination to show the effects of GnRH-dependant estradiol changes on vagina wall, both prior to and 75 minutes after the administration. In Group I, mean serum estradiol 17 beta levels before hormone administration and 75 minutes after the administration were 9.0485 +/- 1.006 pg/ml and 11.1235 +/- 1.199 pg/ml. respectively (p < 0.01). In Group II, mean estradiol 17 beta levels before and after hormone administration were 4.2026 +/- 0.351 pg/ml and 4.2326 +/- 0.354 pg/ml. respectively (p < 0.05). Conclusively, GnRH administration was found to cause an increase in serum estradiol level in bitches with intact ovaries with no obvious change in vaginal epithelial cells. This data may be valuable in investigating the presence of ovary in bitches.