Dopamine, Reward Learning and Sex Hormones

Summary

Hormonal transition periods during the menstrual cycle may predispose women to mental disorders. Hormonal fluctuations provide specific neuroendocrine conditions that modulate brain structure and function and these actions affect cognitive and emotional behaviors and affect energy and mood homeostasis. It is thought that these changes are driven by altered dopamine transmission. Here, the investigators aim to examine (1) how sex hormones and dopamine are linked and also (2) how hormonal changes affect motivation, mood, and energy homeostasis.

To this end, dopamine intervention will be tested on effort-based decision-making and motivational circuits in three hormonal stages (i.e., women in early-follicular phase (EF), women in mid-luteal phase (ML), and men). Additionally, the effects of hormonal status on metabolic indices will be tested, and its effects on mood fluctuations in a period of a month.

The investigator hypothesizes that women in EF cycle phase (1) have naturally less dopamine and show less effort, and (2) they show greater improvement in effort-based decision-making after Levodopa administration. The investigator has exploratory outcomes about (3) sex differences in reward-learning with and without Levodopa administration and explores if these differences correlate with elevated female sex hormone levels. Moreover, it is hypothesized that (4) hormonal fluctuations affect energy homeostasis, thus women in their EF cycle phase have higher energy expenditure and (5) they report more negative mood than in their mid-luteal (ML) cycle phase.

Conditions

• Hormonal Changes
• Menstrual Cycle

Interventions

DRUG

Levodopa administration

To boost dopamine levels 150mg/37.5 mg L-DOPA/benserazide will be administered in line with recent studies (Kroemer et al., 2019). Maximum plasma concentration of Madopar occur \~60 minutes after drug administration. Participants will start the Effort Allocation Task 45 minutes after Levodopa administration.

DRUG

Placebo administration

Placebo tablets will be administered as the placebo-controlled condition.

Sponsors & Collaborators

• German Research Foundation

  collaborator OTHER

• Uppsala University

  collaborator OTHER

• University Hospital Tuebingen

  lead OTHER

Principal Investigators

• Nils B Kroemer, Professor · Department of Psychiatry & Psychotherapy, university of Tübingen

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

20 Years

Max Age

35 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2024-05-31

Primary Completion

2025-12-31

Completion

2025-12-31

Countries

• Germany

Study Locations