Estradiol, and Not Increased Calorie Intake, Determines
Sexual Behavior in Female Common Marmosets
Karli R. Hochstatter¹, Amber K. Edwards¹, David H. Abbott¹˒²
¹Wisconsin National Primate Research Center
²Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI.
% Mounts Accepted
Introduction
 There is strong evidence of the importance of the
hypothalamus in controlling sexual behavior
 The hypothalamus has an array of estrogen receptors
 Female receptivity (sexual acceptance) is estrogendependent
 Low levels of circulating estradiol in women are correlated
with diminished sexual behavior and increased risks of
obesity
 Common marmosets (Callithrix jacchus) serve as well
established models of the female reproductive system
Results
Time Following OVX
(months)
Control (empty)
capsules
Estradiol-filled
capsules
P-Value
2
18% (5/28)
56% (5/9)
p < 0.05
5
9% (3/34)
77% (13/17)
p < 3 x 10-6
Time Following OVX
(months)
Normal Calorie Diet
High Calorie Diet
P-Value
2
36% (4/11)
23% (6/26)
NS
5
29% (4/14)
32% (12/37)
NS
 5 months post-OVX, male mounts correlate with:
 Female sexual receptivity in estradiol-treated females
only (diets combined) (p<0.007)
 Female sexual rejection in control females only (diets
combined) (p<1.8 x 10-5)
 Estradiol tends to enhance female total sexual receptivity
at 5 months following OVX (p < 0.07 vs. controls (diets
combined) at 5 months post OVX)
 5 months post-OVX, frequency of female sexual receptive
behavior positively correlates with necropsy uterine weight
at 6 months post-OVX (all females combined)
 Estradiol and high calorie diet treatment of females do not
alter frequency of male mounts/attempted mounts
 Estradiol, but not high calorie diet, increases female
marmoset sexual receptivity (mount acceptance)
 Behaviors indicative of female anxiety (scratches and long
calls, all females combined) are exclusionary to females
accepting mounts at both 2 and 5 months post OVX
NS: non-significant, P-Value > 0.05
Objective
6.00
Total Mounts and Mount Attempts By Males vs.
Female Rejection in Control Females at 5 Months
7.00
P < 0.007
P < 1.8 x 10-5
6.00
Female Sexual Rejection
5.00
Total Receptivity
 Confirm that estradiol treatment of female marmosets
improves sexual interactions with their male pair-mates 2-5
months following ovariectomy (OVX)
 Examine whether estradiol treatments prevent the
development of diet-induced obesity, and accordingly, if the
obesity affects sexual behaviors in female marmosets 2-5
months following OVX
Total Mounts by Males vs. Total Receptive Behavior
in Estradiol-treated Females at 5 Months
4.00
3.00
2.00
1.00
5.00
4.00
3.00
2.00
1.00
0.00
Behaviors Indicative of Anxiety vs. Accepted Mounts at 5 Months
0.00
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0.00
Total Mounts
2.00
4.00
6.00
8.00
10.00
Total Mounts and Mount Attempts by Males
3
Female Sexually Receptive Behavior
*
5
P < 0.036
E2 Capsule/Normal Diet
5.00
4.00
4.5
p<0.07 vs. controls
*(diets
combined) at 5
Control
3.00
months post OVX
2.00
Accepted Mounts
 15 adult female common marmosets ranging from 2-6 years
of age
 Each female is pair-housed with a testis-intact adult male
 Bilaterally OVX and placed into the following groups:
 Control Empty Silastic capsules, High Calorie Diet (n=4)
 Control Empty Silastic capsules, Normal Calorie Diet
(n=4)
 Estradiol-filled capsules, High Calorie Diet (n=4)
 Estradiol-filled capsules, Normal Calorie Diet (n=3)
 Sexual and affiliative behavior of each pair observed at:
 2 months after OVX
 5 months after OVX
 Behavioral Testing: Each study female was placed in a test
cage out of sight of her male pair-mate. After 90 minutes,
the male pair-mate was introduced into the test cage from
a side cage via a remote door . Behaviors were scored for
15 minutes from within a blind behind a one-way screen.
 Each female received 2 behavioral tests, one week apart, at
both 2 and 5 months after OVX
Total Female Receptivity at 5 months vs. Uterine
Weight at 6 months, all Females Combined
Estradiol
6.00
2
Empty Capsule/High Calorie Diet
Empty Capsule/Normal Diet
1
4
2 Months PostOvariectomy
1.00
0.00
0
0.1
0.2
0.3
0.4
0.5
Uterine weight at 6 months post-OVX (g)
3.5
0.6
Average Number of Occurrences
Methods
Average Frequency of Female
Receptive Behavior per 15 min Test
E2 Capsule/High Calorie Diet
5 Months PostOvariectomy
0
0
10
20
30
40
50
60
70
Scratches + Long Calls
3
2.5
Conclusion
2
1.5
1
0.5
0
Control,
High Calorie
Control,
Normal
Estrogen, Estrogen,
High Calorie Normal
 Sexual behavior between highly compatible, wellestablished pairs of marmosets can be increased when
females have high levels of estradiol (specifically, females
are more willing to copulate with their male mate)
 Anxiety reduces sexual behavior
 High calorie diet does not diminish female marmoset sexual
behavior