Effect of Removal or Stimulation of the Olfactory Bulbs on the Estrous Cycle of the Guinea Pig

The Role of Pheromones in the Regulation of Estrous Cycle Duration in the Guinea Pig

“…low in summer and intermediate in spring; however, VC duration remained constant throughout the year in untreated females and in any group of animals, from I VC of 2 successive cycles to another. Again, there was no difference in VC duration between untreated bulbectomized and unoperated females; in this respect our results confirm those of Donovan and Kopriva [1965], Naturally, in light of the foregoing results we must explain how female guinea pigs, considered sensitive to pheromone action, are unaffected by the olfactory environment of the control group. Perhaps their sensitivity to olfactory cues is too low to allow pheromones, at least under our experimental conditions, to affect estrous cycle duration.…”

“…But for a long time this was not recognized in the rat and guinea pig. Rosen et al [1940], Van der Werff ten Bosch and Van Beugen [1960], Orbach and K ling [1966] and Moss [1971], working with the former, and Donovan and Kopriva [1965] with the latter, stated that olfactory bulbectomy did not alter estrous cycle duration. However, recent work has proven that olfactory bulb deprivation could modify estrous rhythm in the rat [Aron et al, 1971[Aron et al, , 1972Roos et al, 1973] and that exposing females to the odor of male or female urine [Aron and Chateau, 1971;Chateau et al, 1972;1973;A r o n , 1973] could shorten estrous cycle duration in this species.…”

Effect of Electrochemical Stimulation in the Olfactory Bulbs on the Release of Gonadotropin Hormones in Rats

“…A fa cilitation of gonadotropin hormone secretion by olfactory stimuli could be inferred from studies showing that ablation of the olfactory bulbs in rats delayed the onset of sexual ma turity [filing, 1964;Orbach and filing, 1966], and that exposure of immature female mice to an adult male accelerates sexual maturation [Vanderberg, 1967[Vanderberg, , 1969Bronson, 1975], fa cilitates ovulation following treatment with either pregnant mare serum or human chori onic gonadotropin [Zarrow et al, 1973] and produces release of LH [Bronson and Des jardins, 1974], These latter effects appear to be associated with olfactory stimuli, since the esposure of immature mice to male urine also resulted in a release of LH [Bronson and Maruniak, 1976]. In adult animals, cyclic va ginal estrus was not altered after the removal of the olfactory bulbs of guinea pigs [Donovan andKopriva, 1965], rats [van der Werff ten Bosch andvan Beugen, 1960;Rosen et al, 1940;van Beugen and van der Werff ten Bosch, 1961], rabbits [Brooks, 1937;Sawyer, 1956] or fer rets [van der Werff ten Bosch, 1963], But shortening of estrous cycle's duration was ob served in female rats [Aron, 1973], guinea pigs [Jesel and Aron, 1976] and mice [Whitten, 1958] exposed to the odor of urine from males of the same species. Furthermore, olfactory bulb ablation caused a decrease of ovarian and uterine weights in mice [Whitten, 1956], but failed to affect ovulation induced by coitus in the rabbit [Brooks, 1937;Sawyer, 1956] and in the rat [Aron et al, 1970], al though Curry [1974] has reported that the removal of the olfactory bulbs in rats reduced the number of animals ovulating after mating, and the number of ova shed was lower than in the controls.…”

Biology and Diseases of Guinea Pigs

“…There is no conclusive evidence of cycle synchronization among group-housed sows (Donovan and Kopriva, 1965;Harned and Casida, 1972). Estrus can be synchronized with progesterone administered orally or as a subcutaneous implant (Ueda et al, 1998;Gregoire et al, 2012).…”