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Updated: Apr 19, 2026
07:35
Laser Microdissection-Based Protocol for the LC-MS/MS Analysis of the Proteomic Profile of Neuromelanin Granules
Published on: December 16, 2021
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Parkinson's disease-associated melanin steal
Marty Hinz1, Alvin Stein2, Ted Cole3
1Clinical Research, NeuroResearch Clinics, Inc., Cape Coral, FL, USA.
Neuropsychiatric Disease and Treatment
|December 20, 2014
Summary
Urinary dopamine fluctuations in Parkinson's disease patients were observed to decrease with L-tyrosine. This study investigates if a "melanin steal" phenomenon causes these dopamine level changes.
Area of Science:
- Neuroscience
- Biochemistry
Background:
- Urinary dopamine fluctuations in a competitive inhibition state were first documented in 2009.
- Higher daily doses of L-tyrosine were noted to reduce the magnitude of these fluctuations.
Purpose of the Study:
- To document current knowledge on managing retrograde phase 1 dopamine fluctuations.
- To investigate the hypothesis that these fluctuations are caused by a melanin steal phenomenon.
Main Methods:
- Extensive statistical analysis performed by authors since 2004.
- Formulation of a plausible explanation in 2012.
- Defined correlations between L-tyrosine administration and Parkinson's disease on/off effect.
Main Results:
- Progressively higher daily dosing values of L-tyrosine decreased the magnitude of urinary dopamine fluctuations.
- Correlations between L-tyrosine administration and the on/off effect of Parkinson's disease were defined.
Conclusions:
- The study investigates the melanin steal phenomenon as a cause for retrograde phase 1 dopamine fluctuations.
- Further research is needed to confirm the melanin steal hypothesis and its management implications.
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