Sex Difference and Testosterone Modulation: RESULTS(4)

18 Mar
2013

RESULTS(4)

A sexual dimorphism was observed in the ability of male odors to elicit significant neuronal Fos-IR responses in more central segments of the chemosensory pathway. Thus male odors stimulated neuronal Fos-IR in the BNST of both sexes (F = 8.034, p < 0.05; Table 1); however, this effect was significantly stronger in female than in male subjects (F = 5.904, p < 0.05). Only females showed significant increases in neuronal Fos-IR in the mPOA (F = 5.528, p < 0.05) and in the VLH (F = 6.516, p < 0.05) after exposure to male bedding (Table 1). buy flovent inhaler

Experiment 3: Effects of Chemosensory Cues and Testosterone Treatment on Scent-gathering Behavior

There was no indication that the ability of TP treatment to enhance ferrets’ neuronal Fos-IR responses to estrous female odors (experiment 1) resulted from increased locomotor activity or scent-gathering behaviors in steroid-treated subjects. Treatment with TP actually reduced locomotor activity in males, but not in females, regardless of which olfactory stimulus was present at the time of assessment (Table 2). This was reflected in a significant sex X steroid treatment interaction (F = 15.413, p < 0.01). Exposure to odors from estrous females or breeding males caused significant increases in sniffing behavior (F = 20.633, p < 0.01) in both sexes; however, these increments were similar in gonadectomized subjects given TP as opposed to oil vehicle.

TABLE 1. Total number of Fos-IR cells (mean ± SEM) per standard area in gonadectomized, TP-treated male and female ferrets after exposure to either a clean cage or to soiled bedding from a breeding male (experiment 2).

BrainregionFemalesubjectsMale subjects
Clean cage control (n=3)Malebedding(n=4)Clean cage control (n = 5)Malebedding(n=5)
MOBra48 ± 13108 ± 34*29 ± 984 ± 24*
MOBcb104 ± 13154 ± 38*42 ± 10112 ± 24*
MOBcac72 ± 20156 ± 18*33 ± 1399 ± 34*
AOB5±310 ± 26±29±3
MA10 ± 330 ± 7*8±222 ± 3*
BNST15±883 ± 28*+6±121 ± 8*
VLH17 ± 259 ± 19*+10±217±3
mPOA6±036 ± 13*+5±16±1
dPOA/AH7±216 ± 64±17±2
vPOA/AH2±110 ± 61±13±1

a MOBr, rostral (+18.8 mm). b MOBc, central (+16.4 mm). c MOBca, caudal ( + 14.5 mm).
* p < 0.05; Student Neuman-Keuls post-hoc comparisons with same-sex, clean-cage controls.
+ p < 0.05; Student Neuman-Keuls post-hoc comparisons with males exposed to male bedding.

TABLE 2. Effect of TP treatment on locomotor activity and scent-gathering behaviors displayed by gonadectomized female and male ferrets placed for 30 min either in a clean cage or in a cage containing pheromones from soiled bedding from either an estrous female or a breeding male ferret (experiment 3).

SexHormone treatmentOlfactory stimulusBehavioral parameterGrid crossings3 Sniffing (totala (total number) duration in sec)
FemaleOilClean cage371 ± 48110 ± 48
Estrous bedding351 ± 9289 ± 26*
Male bedding295 ± 27288 ± 45*
TPClean cage422 ± 31181 ± 31
Estrous bedding346 ± 34340 ± 27*
Male bedding321 ± 18336 ± 40*
MaleOilClean cage267 ± 33104 ± 14
Estrous bedding347 ± 39225 ± 33*
Male bedding335 ± 29233 ± 62*
TPClean cage247 ± 28+104 ± 28
Estrous beddingcc2±52318 ± 53*
Male bedding230 ± 29+190 ± 33*

a Data are expressed as mean ± SEM; n = 5.
* p < 0.05; Student Neuman-Keuls post-hoc comparisons with same-sex clean-cage controls. + p < 0.01; represents a significant three-way ANOVA sex X steroid interaction.

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