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[Pathomechanism of vitamin D intoxication]
Iwona Rybakowska1, Jerzy Klimek, Krystian Kaletha
1Zakład Biochemii i Fizjologii Klinicznej Gdańskiego Uniwersytetu Medycznego, Gdańsk.
Przeglad Lekarski
|March 11, 2011
Summary
Vitamin D intoxication involves elevated vitamin D precursor [25(OH)D3] but not its active form [1alpha,25(OH)2D3]. The precursor likely releases the active form from binding proteins, stimulating gene transcription.
Area of Science:
- Endocrinology
- Molecular Biology
- Biochemistry
Context:
- The precise mechanism behind vitamin D intoxication remains poorly understood.
- Previous animal studies indicate elevated serum levels of the vitamin D precursor, 25(OH)D3, during intoxication.
- Notably, the hormonally active form, 1alpha,25(OH)2D3, does not show similar elevation.
Purpose:
- To elucidate the pathomechanism of vitamin D intoxication.
- To explain the differential serum level changes between vitamin D precursor and its active form during intoxication.
Summary:
- Experiments in animal models revealed that vitamin D intoxication is characterized by significantly increased serum levels of the vitamin D precursor, 25(OH)D3.
- Conversely, the hormonally active form, 1alpha,25(OH)2D3, did not exhibit elevated serum concentrations.
- The study proposes that the vitamin D precursor displaces the active form from its binding with serum transport protein (DBP).
- This displacement is hypothesized to stimulate gene transcription in target tissues, thereby contributing to intoxication.
Impact:
- Provides a potential molecular mechanism for vitamin D intoxication.
- Highlights the role of the vitamin D precursor and its interaction with DBP.
- Suggests new avenues for understanding and potentially managing vitamin D toxicity.
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