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D2 Dopamine Receptor on Human Aldosterone-Producing Adenoma and Its Role in Aldosterone Secretion and Cell Proliferation

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ClinicalTrials.gov Identifier: NCT00173446
Recruitment Status : Unknown
Verified August 2005 by National Taiwan University Hospital.
Recruitment status was:  Recruiting
First Posted : September 15, 2005
Last Update Posted : June 8, 2007
Information provided by:
National Taiwan University Hospital

Brief Summary:
Dopamine (DA) is one of the main catecholamines in mammals. Its major role as a brain neurotransmitter is well known as well as its contribution to the development of pathologies, mainly arterial hypertension. Traditionally, dopamine receptors are divided into two families according to the stimulation or inhibition they may produce at the adenyl cyclase level. Five dopamine receptors have been identified: D1 (D1a) and D5 (D1b) exist in the D1 family. D2s, D2l, D3 and D4 belong to the D2 family. Formerly, less than 1% of patients with hypertension were believed to have primary hyperaldosteronism; however, recent studies have suggested that primary aldosteronism affects 5-13% of patients with hypertension and aldosteronomas are a more common cause of hypertension than previously thought. At least 2% of patients with hypertension may have an aldosteronoma. The investigators' previous clinical observation found two subtypes of aldosterone-producing adenoma (APA), which were defined according to their responses to metoclopramide during salt manipulation. On a high-salt diet (HS), the nonsuppressible subjects, with less dopaminergic inhibition of aldosterone secretion, had less urinary DA excretion and greater blood pressure (BP) elevation [Wu KD et al. 2002]. The investigators' recent study of six patients with an APA found that the expression of the D2 receptor in APA was not universal. The amounts of D2 receptor messenger ribonucleic acid (mRNA) were more variant in either APA or their remnant adrenal glands. Only two cases of APA expressed the D2 receptors with much weaker signals compared with those in their respective remnant adrenals [Wu KD et al. 2001]. The investigators' current work demonstrates that the D2 receptor negatively regulates AII-stimulated aldosterone secretion and aldosterone synthase mRNA expression in NCI-H295R cells. On the other hand, the D4 receptor counteracts with the effect of the D2 receptor. In a future study, the investigators wish to quantify D2 and D4 receptor mRNA and protein expression in APA and their remnant adrenal glands and correlate them to their clinical metoclopramide test results. The investigators also wish to know whether the difference between the D2 and D4 receptor expression reflect the different effects of dopamine inhibition on AII-stimulated aldosterone secretion and aldosterone synthase transcription. Finally, the investigators will explore the role of D2 and D4 receptors on AII-stimulated adrenal cell proliferation.

Condition or disease
Hypertension Adrenal Aldosterone-Producing Adenoma

Study Type : Observational
Estimated Enrollment : 30 participants
Observational Model: Defined Population
Primary Purpose: Screening
Time Perspective: Cross-Sectional
Time Perspective: Retrospective
Official Title: Expression of D2-Like Dopamine Receptor of Human Aldosterone-Producing Adenoma and Its Role in Regulation of Aldosterone Secretion and Cell Proliferation
Study Start Date : January 2002

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Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Adrenal aldosterone-producing adenoma

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 ClinicalTrials.gov identifier (NCT number): NCT00173446

Contact: Hong-Wei Chang 886223123456 ext 5762 chianghongwei@yahoo.com.tw

National Taiwan University Hospital Recruiting
Taipei, Taiwan, 100
Contact: Hong-Wei Chang    886223123456 ext 5762    chianghongwei@yahoo.com.tw   
Sponsors and Collaborators
National Taiwan University Hospital
Principal Investigator: Hong-Wei Chang National Taiwan University Hospital

ClinicalTrials.gov Identifier: NCT00173446     History of Changes
Other Study ID Numbers: 9461700673
First Posted: September 15, 2005    Key Record Dates
Last Update Posted: June 8, 2007
Last Verified: August 2005

Keywords provided by National Taiwan University Hospital:
Normal part of the adrenal gland

Additional relevant MeSH terms:
Neoplasms, Glandular and Epithelial
Neoplasms by Histologic Type
Cardiotonic Agents
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Dopamine Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Protective Agents