Female hamster preference for odors is not regulated by circulating gonadal hormones

Abstract

Proceptive and receptive behaviors of female rodents, such as golden hamsters, are often regulated by changes in circulating levels of ovarian hormones. However, less is known about how ovarian hormones might regulate female hamster's attraction and preference for volatile odor from males. To evaluate this, we assessed female preference by recording investigation and proximity to male and female volatile odorants in a Y-maze across all days of the estrous cycle (Experiments 1 and 2) or following ovariectomy (Experiment 3). In Experiment 1, female subjects were tested four times, once on each day of their estrous cycle. Females showed a preference for male odors on diestrus day 1 and to a lesser degree on proestrus, but showed no preference on the day of behavioral estrus. Irrespective of cycle day, preference was apparent in the first few days of testing and disappeared by the fourth day, suggesting that repeated testing attenuated female preference. To avoid this problem, in Experiment 2 each animal was tested only on one day of the 4-day estrous cycle. Female preference for male volatile odors over those from females was observed on each day of their estrous cycle, including estrus. Moreover, following gonadectomy (Experiment 3) female hamsters still preferred male volatile odors to those of females. Taken together, this suggests that circulating levels of gonadal hormones do not influence preference for male volatile odors in female hamsters.

The medial preoptic area is necessary for sexual odor preference, but not sexual solicitation, in female Syrian hamsters

“…Neurons in MPOA express receptors for estradiol and progesterone (Du et al, 1996; Li et al, 1993), and gonadal steroids strongly regulate other precopulatory behaviors that are disrupted following MPOA lesions, such as ultrasonic vocalizations (Floody, 1989; Floody et al, 1979). Although there is evidence in rats to suggest that estrogen alone or estrogen plus progesterone treatment may enhance the preference for male stimuli in females (Clark et al, 2004; Xiao et al, 2005), this does not appear to be the case in either mice (Moncho-Bogani et al, 2004) or hamsters (Eidson et al, 2007). Indeed, female hamsters display a robust preference for male odors across the estrous cycle (Eidson et al, 2007; Martinez and Petrulis, 2011; Martinez et al, 2010) and following ovariectomy (Eidson et al, 2007).…”

“…Although there is evidence in rats to suggest that estrogen alone or estrogen plus progesterone treatment may enhance the preference for male stimuli in females (Clark et al, 2004; Xiao et al, 2005), this does not appear to be the case in either mice (Moncho-Bogani et al, 2004) or hamsters (Eidson et al, 2007). Indeed, female hamsters display a robust preference for male odors across the estrous cycle (Eidson et al, 2007; Martinez and Petrulis, 2011; Martinez et al, 2010) and following ovariectomy (Eidson et al, 2007). Therefore, it seems unlikely that either estradiol or progesterone acts within MPOA to critically regulate the expression of sexual odor preference in female hamsters.…”

“…This dissociation may allow for these two behaviors to be differentially regulated by internal or external factors. Indeed, vaginal marking is disrupted following either ovariectomy or blockade of oxytocin receptors, whereas sexual odor preference is normally expressed despite these manipulations (Eidson et al, 2007; Martinez et al, 2010; Takahashi and Lisk, 1983). …”

Neural mechanisms of individual and sexual recognition in Syrian hamsters (Mesocricetus auratus)

“…However, unlike male hamsters [89,92], females do not require high levels of circulating sex steroids to show an investigatory preference for opposite-sex odors. That is, females show preference for male odors across all days of the estrous cycle and even following ovariectomy [16]. As such, the neural mechanisms regulating chemoinvestigatory preference in females may be under less hormonal control than those of male hamsters.…”

Chemosignals, hormones and mammalian reproduction

“…However, significant species differences exist in the hormone sensitivity of female attraction to male chemosignals. Female Syrian hamsters are attracted to male chemosignals across their entire estrous cycle (not just during estrus) and during lactation but not during pregnancy (Eidson et al, 2007; Johnston, 1979). Female meadow voles are attracted to male scents across pregnancy and also during lactation (Ferkin and Johnston, 1995).…”