[Abstract Title]. - Society for Neuroscience

Poster
284. Regulation of Food Intake and Body Weight: Integration of Peripheral Signals:
Systems
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 284.4/PP27
Topic: E.07.b. Integration of peripheral signals: Systems
Support: HD46501
RR00165
Title: Progesterone reverses the adverse consequences of psychosocial stress and estradiol on
body weight
Authors: *V. MICHOPOULOS, J. B. HOFFMAN, E. KESSLER, M. E. WILSON;
Yerkes Natl. Primate Rese Ctr., Emory Univ., Lawrenceville, GA
Abstract: Chronic stress exposure and the upregulation of corticotropin releasing hormone
(CRH) in animals reduce both body weight (BW) and intake of standard low fat, high fiber diets.
Food intake and BW are also attenuated by estradiol (E2) exposure as BW decreases in response
to E2 and fall during the cycle when E2 is elevated. While E2‟s action is thought to be due to a
change in orexigenic signaling, progesterone promotes food intake and weight gain, as seen
during the luteal phase and pregnancy. However, it remains unclear how progesterone interacts
with E2 to influence BW. Additionally, the relationship between stress exposure and ovarian
hormones on the regulation of BW is poorly understood. In order elucidate these relationships,
the present study tested the hypothesis that E2 would exacerbate the adverse consequences of
stress on BW and that these effects would be attenuated by co-administration with progesterone.
Socially housed female rhesus monkeys provide an ethologically valid model to investigate the
adverse consequences of psychosocial stressors as subordinate females are under continuous
harassment by dominant animals, leading to a dysregulation of the hypothalamic-pituitaryadrenal
axis. Ovariectomized females fed a low fat, high fiber chow ad libitum were studied
under four conditions (control, E2, progesterone, and E2 plus progesterone) in a counterbalanced
manner over 4 weeks. Social status had a significant effect on BW, as dominant females were
consistently heavier than subordinates throughout the 16-week study (p=0.026). E2 significantly
reduced BW (p=0.010), regardless of status (p=0.503). Progesterone significantly increased BW
in all females even during co-administration with E2 (p