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Localización de la 11 beta-hidroxisteroide deshidrogenasa--protector específico del tejido del receptor de los
C R Edwards1, P M Stewart, D Burt
1Department of Medicine, Western General Hospital, Edinburgh, UK.
Lancet (London, England)
|October 29, 1988
Resumen
El receptor de mineralocorticoides está protegido de la corticosterona por la 11 beta-hidroxisteroide deshidrogenasa (11 beta-OHSD) en tejidos selectivos. Esta enzima es la enzima
Área de la Ciencia:
- Endocrinología Endocrinología.
- Biología Molecular Biología Molecular
- Fisiología Fisiología Fisiología.
Sus antecedentes:
- El receptor de mineralocorticoides (MR) exhibe una unión no específica a la aldosterona y el cortisol in vitro.
- In vivo, la selectividad tisular para la aldosterona existe a pesar de la naturaleza no específica de la RM.
- Esta selectividad se observa en tejidos como el riñón y la glándula parótida, pero no en el hipocampo o el corazón.
Objetivo del estudio:
- Investigar el mecanismo detrás de la selectividad de la aldosterona en tejidos específicos.
- Determinar el papel de la 11 beta-hidroxisteroide deshidrogenasa (11 beta-OHSD) en la regulación de la actividad de la RM.
- Para explicar las consecuencias fisiológicas de la deficiencia o inhibición de 11 beta-OHSD.
Principales métodos:
- Los experimentos se llevaron a cabo en ratas.
- La concentración tisular de 11 beta-OHSD se midió en tejidos selectivos y no selectivos.
- Se realizaron estudios autoradiográficos para evaluar la unión al receptor después de la inhibición de la enzima.
Principales resultados:
- 11 beta-hidroxisteroide deshidrogenasa (11 beta-OHSD) se encontró en concentraciones más altas en los tejidos selectivos de aldosterona.
- La localización de la enzima sugiere un mecanismo de protección paracrino o autocrino contra la corticosterona.
- La inhibición de 11 beta-OHSD condujo a la pérdida de protección, con sitios de unión similares para la corticosterona y la aldosterona.
Conclusiones:
- La 11 beta-hidroxisteroide deshidrogenasa (11 beta-OHSD) confiere la selectividad de la aldosterona a tejidos específicos al metabolizar la corticosterona.
- Esta actividad enzimática protege el receptor de mineralocorticoides de la saturación por la corticosterona.
- Los hallazgos explican condiciones como la hipertensión y la hipocalemia asociadas con la deficiencia de 11 beta-OHSD o la ingestión de regaliz.
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