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Effects of Sex Steroids on the Serotonin System

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT02715232
Recruitment Status : Recruiting
First Posted : March 22, 2016
Last Update Posted : October 15, 2018
Information provided by (Responsible Party):
Rupert Lanzenberger, Medical University of Vienna

Brief Summary:
The aim of this study is to prove the modulatory influence of sex hormones on serotonergic neurotransmission by determining the enzymatic processes involved in serotonin synthesis and degradation using positron emission tomography (PET) in humans in vivo with the radiotracers [11C]AMT and [11C]harmine.

Condition or disease Intervention/treatment Phase
Gender Dysphoria Drug: Testosterone Drug: Lynestrenol Drug: Cyproterone Acetate Drug: Estradiol Drug: Triptorelin acetate Phase 4

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 92 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Effects of Sex Steroid Hormones on Serotonin Synthesis and Degradation Measured With PET
Actual Study Start Date : February 6, 2017
Estimated Primary Completion Date : December 2020
Estimated Study Completion Date : December 2020

Arm Intervention/treatment
Experimental: Female-to-Males
Female-to-Male Transsexuals receiving Testosterone treatment
Drug: Testosterone
100mg testosterone undecanoat every 8-12 weeks, or alternatively 50mg testosterone transdermally, or 50mg testosterone creme

Drug: Lynestrenol
2-3 tablets/day, if menstruation still occurs

Drug: Triptorelin acetate
4,12mg every 4-6 weeks (powder for suspension for injection s.c. or i.m.

Experimental: Male-to-Females
Male-to-Female Transsexuals receiving Estradiol and Anti-androgen treatment
Drug: Cyproterone Acetate
25mg daily

Drug: Estradiol
75 microgram transdermal therapeutic system twice a week, or p.o. estradiol 2x2mg/day, or estradiol gel 1,5-3mg

Drug: Triptorelin acetate
4,12mg every 4-6 weeks (powder for suspension for injection s.c. or i.m.

No Intervention: Female Controls
Female Controls receiving no intervention
No Intervention: Male Controls
Male controls receiving no intervention

Primary Outcome Measures :
  1. blood-to-brain clearance/trapping (K*) of [11C]AMT [ Time Frame: <5 months ]
    [11C]AMT trapping as an estimation of brain serotonin synthesis in vivo in humans

  2. distribution volume (DV) of [11C]harmine [ Time Frame: <5 months ]
    distribution volume of specifically bound radioligand [11C]harmine in brain regions

Secondary Outcome Measures :
  1. white and gray matter microstructure [ Time Frame: <5 months ]
    microstructure measured using diffusion weighted imaging

  2. gray matter volume/density and cortical thickness [ Time Frame: <5 months ]
    structural MRI measurements

  3. cerebral blood flow (CBF) [ Time Frame: <5 months ]
    cerebral blood flow measured using arterial spin labeling MRI

  4. Scores on the Klein Sexual Orientation Grid (KSOG) [ Time Frame: <5 months ]
    the KSOG measures sexual orientation

  5. Scores on the Utrecht Gender Dysphoria Scale [ Time Frame: <5 months ]
    Score for gender dysphoria

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • DSM-5 diagnosis of Gender Dysphoria (DSM-5: 302.85; ICD-10: F64.1) (for transsexuals only)
  • Somatic health based on history, physical examination, ECG, laboratory screening, SCID
  • willingness and competence to sign the informed consent form

Exclusion Criteria:

  • concomitant major medical or neurological illness
  • internal or neurologic medical histories as well as pregnancy (positive urine pregnancy test) or breastfeeding
  • other DSM-5 Axis-I comorbidities, determined by a structured clinical interview (SCID), especially body dysphoric disorder (DSM-5: 300.7; ICD-10: F45.22), schizophrenia spectrum and other psychotic disorders
  • steroid hormone treatment within 6 months prior to inclusion
  • treatment with psychotropic agents such as SSRIs
  • any implant or stainless steel graft
  • abnormal values in routine laboratory screening or general physical examination
  • current substance abuse or current or past substance related disorder
  • for participants who participated in an earlier neuroimaging study using ionizing radiation, the total radiation exposure dose of 20 mSv over the last 10 years must not be exceeded, as specified in the legislation on radiation protection (Allg. Strahlenschutzverordnung 2010;
  • failure to comply with the study protocol or to follow the instructions of the investigating team

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02715232

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Contact: Rupert Lanzenberger, MD +43 40400 ext 35760
Contact: Georg S Kranz, PhD +43 40400 ext 38250

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Department of Psychiatry and Psychotherapy, Medical University of Vienna Recruiting
Vienna, Austria, 1090
Contact: Rupert Lanzenberger, A/Prof.    +43 40400 ext 3825   
Principal Investigator: Rupert Lanzenberger, A/Prof. MD         
Sponsors and Collaborators
Medical University of Vienna
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Principal Investigator: Rupert Lanzenberger, MD Department of Psychiatry and Psychotherapy, Medical University of Vienna

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Responsible Party: Rupert Lanzenberger, Assoc. Prof., Medical University of Vienna Identifier: NCT02715232    
Other Study ID Numbers: 1.1-20150511
First Posted: March 22, 2016    Key Record Dates
Last Update Posted: October 15, 2018
Last Verified: October 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Gender Dysphoria
Sexual Dysfunctions, Psychological
Mental Disorders
Triptorelin Pamoate
Cyproterone Acetate
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs
Contraceptive Agents
Reproductive Control Agents
Contraceptive Agents, Female
Antineoplastic Agents, Hormonal
Antineoplastic Agents
Luteolytic Agents
Androgen Antagonists
Hormone Antagonists
Contraceptive Agents, Male
Contraceptives, Oral, Synthetic
Contraceptives, Oral