Effects of Corpus Luteum Removal on Ovarian Cyclicity of the Rat

Effects of Pseudopregnancy and Ergocornine Treatment on Synchronization of Mating, Duration of Gestation and Production of Young in Rats

“…The results of the present study suggest that the chemical-induction of luteolysis does hold promise as a method for synchronizing estrus in domestic animals. The study of Smalstig et al (1971) indicates that the pseudopregnant rat is probably an acceptable model for evaluating the process of induction of luteolysis as a means of synchronizing estrus in domestic species. The level of fertility found in this study in the ergocornine-treated pseudopregnant rats compared to their pseudopregnant controls, although slightly reduced, is reasonably high if one considers the reproductive performance expected in domestic animals mated at first synchronized estrus when progestins are used (Baker et al, 1954;Hansel, 1967;Robinson, 1967).…”

“…The discovery that prostaglandin F2c~ is luteolytic in a number of species, (Blatchley and Donovan, 1969;Louis et al, 1973;Mc-Cracken et al, 1970;Pharriss et al, 1972;Pharriss and Wyngarden, 1969;Thorburn and Nicol, 1971) has stimulated interest in the use 1 We would like to thank Dr. R. L. Elton, Sandoz Pharmaceuticals, Hanover, NJ, for the generous gift of ergocornine hydrogenmaleate used in this study. We are also indebted to Dr. L. E. Casida of luteolysis as a method for synchronizing estrus in mammals (Inskeep, 1973;Lauderdale et al, 1974;Shaar et al, 1975;Smalstig et al, 1971;Tervit et al, 1973). The following is a study using the rat as a model to evaluate induced luteolysis as a method for synchronizing estrus in mammals in general and in the rat specifically (Smalstig et al, 1971).…”

“…We are also indebted to Dr. L. E. Casida of luteolysis as a method for synchronizing estrus in mammals (Inskeep, 1973;Lauderdale et al, 1974;Shaar et al, 1975;Smalstig et al, 1971;Tervit et al, 1973). The following is a study using the rat as a model to evaluate induced luteolysis as a method for synchronizing estrus in mammals in general and in the rat specifically (Smalstig et al, 1971). The luteolytic agent used was ergocornine hydrogenmaleate, one of the group of ergot derivatives known to be luteolytic in the rat (Kraicer and Shelesnyak, 1965a,b;Lindner and Shelesnyak, 1967;Lobel et al, 1966;Shelesnyak, 1957).…”

The Effects of 5-Bromo-2-Thienyl-Ethyl-Ketone Thiosemicarbazone on Ovarian Cyclicity and Ovulation in the Rat

“…For this reason, the following series of experi¬ ments was designed to determine the incidence and interval to return of prooestrous and/or oestrous vaginal smears in pseudopregnant rats treated with 70026, to establish whether or not ovulation accompanied these smears, and to resolve whether 70026 had an effect on ovulation in the rat. (Shelesnyak, 1957; Effects of 70026 on ovarian cyclicity in rats 423 Kraicer & Shelesnyak, 1965a, b, 1968Kisch & Shelesnyak, 1968) (Lipner & Greep, 1971;Ying & Greep, 1971) (Kraicer & Shelesnyak, 1968) or subjected to ablation of CL (Smalstig et al, 1971). These two procedures to reduce progesterone secretion in the pseudopregnant rat, however, result in ovulation as well as the appearance of pro-oestrous and/or oestrous vaginal smears (Kraicer & Shelesnyak, 1968;Kraicer, 1969;Smalstig et al, 1971).…”

“…(Shelesnyak, 1957; Effects of 70026 on ovarian cyclicity in rats 423 Kraicer & Shelesnyak, 1965a, b, 1968Kisch & Shelesnyak, 1968) (Lipner & Greep, 1971;Ying & Greep, 1971) (Kraicer & Shelesnyak, 1968) or subjected to ablation of CL (Smalstig et al, 1971). These two procedures to reduce progesterone secretion in the pseudopregnant rat, however, result in ovulation as well as the appearance of pro-oestrous and/or oestrous vaginal smears (Kraicer & Shelesnyak, 1968;Kraicer, 1969;Smalstig et al, 1971). The results of Mason et al (1969) suggest that 70026 may not completely suppress the ovarian progesterone secretion in the rat, while the report of Kraicer (1969) suggests that suppression of vaginal cornification in the rat requires more endo¬ genous progesterone than does suppression of ovulation.…”