# Ovarian Hormones, Reward Response, and Binge Eating in Bulimia Nervosa: An Experimental Design

> **NIH NIH R21** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2020 · $155,500

## Abstract

PROJECT SUMMARY
Human observational studies suggest ovarian hormones are involved in the neurobiology of bulimia nervosa
(BN), specifically the symptom of binge eating: cumulatively, it appears that low estradiol (E2) or progesterone
(P4) antagonized E2 are associated with increased binge eating. Problematic however, is that the effect of
ovarian hormones on BN symptoms in humans has been inferred from animal studies and from changes in
behavior occurring with presumed and measured levels of hormones during the menstrual cycle. Such
observational studies cannot conclude a causal, mechanistic link. Moreover, why ovarian hormones influence
symptom onset or fluctuation is unknown. Given that ovarian hormones, specifically E2, have pronounced
effects on reward processing and neuropathways and neurotransmitters (e.g., dopamine) involved in reward,
E2 may influence binge eating through its effect on reward processes that are altered in BN. Thus, we
hypothesize BN represents a hormone sensitive phenotype and this sensitivity is displayed as an impaired
reward response (i.e., reward-related inhibitory control deficits, heightened reward sensitivity, impaired delay
discounting) in the context of low E2. Because women with BN represent a subgroup of the population with
reduced dopamine activity, which is enhanced by E2, low E2 may promote reward-motivated behaviors such
as binge eating via dopamine withdrawal. We propose this proof-of-concept study to examine our overarching
hypothesis. We will complete a 3-month longitudinal, within-person experimental design that parallels animal
models to directly manipulate ovarian hormones in females with BN (N = 10): temporarily inducing
hypogonadism using a GnRH agonist and then addback E2 and P4 independently in a double-blind cross-over
manner. During each phase of the manipulation, subjects will complete symptom reports of binge eating and
behavioral tasks and questionnaires of reward processing and reward response. We will complete the following
aims: 1): Quantify the direct effect of E2 and P4 on binge eating in women with BN; 2): Determine the effect of
E2 on reward response (e.g., delay discounting) and related correlates (e.g., behavioral inhibition); 3): Examine
the association between reward response and binge eating before and after E2 addback. If BN truly represents
a hormone sensitive phenotype, we will see direct change in binge eating during the hormone challenge.
Based on our previous work, we expect to see a beneficial effect of E2 and an exacerbating effect of P4. An
experimental design is the only way we can confidently explore the direct impact of ovarian hormones on BN.
This high-risk proposal has significant potential for high-reward. Successful completion of the aims will provide
guidance in regard to if (and how) E2 and P4 directly affect binge eating in BN. This will provide the empirical
direction needed for the investigators to complete a larger, hypothesis-driven mechanistic trial, in tur...

## Key facts

- **NIH application ID:** 10021706
- **Project number:** 5R21MH121726-02
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Jessica H Baker
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $155,500
- **Award type:** 5
- **Project period:** 2019-09-23 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10021706

## Citation

> US National Institutes of Health, RePORTER application 10021706, Ovarian Hormones, Reward Response, and Binge Eating in Bulimia Nervosa: An Experimental Design (5R21MH121726-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10021706. Licensed CC0.

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