Diese Präsentation wurde erfolgreich gemeldet.
Wir verwenden Ihre LinkedIn Profilangaben und Informationen zu Ihren Aktivitäten, um Anzeigen zu personalisieren und Ihnen relevantere Inhalte anzuzeigen. Sie können Ihre Anzeigeneinstellungen jederzeit ändern.
DISORDERS IN DEGRADATION OFHORMONES BY KIDNEYDr SIVARAJ SDEPT OF PHYSIOLOGYALL INDIA INSTITUTE OF MEDICAL SCIENCESNEW DELH...
• Uremia interferes with metabolism andregulation of hormones by various mechanism• Endocrine defects occurs due to– Inapp...
Metabolism of peptide hormonesMost polypeptide hormones almost freelyfiltered in the glomerulus Intratubular (brush bord...
Metabolism of peptide hormonesIntratubular&IntracellulardegradationUptake fromperitubularbloodEmmanouel DS et al.,1980
Increased Plasma HormoneConcentrations• Reduction of renal mass result in decrease inthe metabolic clearance• If catabolic...
• Extrarenal hormone elimination may also bereducede.g., degradation of insulin in skeletal muscle tissueis diminished• Hy...
Decreased Plasma HormoneConcentrations• The reduction in functional renal mass maincause for decreased levels of hormonesp...
• Extra renal hormones decreased when thehormone-producing gland is the final effectororgan of complex hormonal axise.g., ...
Disorders of Hormone ActionHormone Binding to Plasma Proteins– Excessive concentrations of several insulin-likegrowth fac...
Disturbed Activation of Prohormones– Peripheral conversion of T4 to tissue active T3 isimpaired• Low T3 syndrome– Chronic...
Alterations of Target Tissue Sensitivity• Reduced cellular receptor activation due tothe diminished receptor abundance• P...
Disorders of Degradation of hormones by kidney
Nächste SlideShare
Wird geladen in …5
×

Disorders of Degradation of hormones by kidney

920 Aufrufe

Veröffentlicht am

Disorders of Degradation of hormones by kidney

Veröffentlicht in: Gesundheit & Medizin, Technologie
  • Als Erste(r) kommentieren

Disorders of Degradation of hormones by kidney

  1. 1. DISORDERS IN DEGRADATION OFHORMONES BY KIDNEYDr SIVARAJ SDEPT OF PHYSIOLOGYALL INDIA INSTITUTE OF MEDICAL SCIENCESNEW DELHI23/04/2013
  2. 2. • Uremia interferes with metabolism andregulation of hormones by various mechanism• Endocrine defects occurs due to– Inappropriate circulating hormone concentration– Altered hormone action at target tissue level
  3. 3. Metabolism of peptide hormonesMost polypeptide hormones almost freelyfiltered in the glomerulus Intratubular (brush border peptidases) Intracellular (cytosolic or lysosomal) degradationin tubular cellIn certain hormones Receptor-mediated uptakeEmmanouel DS et al.,1980
  4. 4. Metabolism of peptide hormonesIntratubular&IntracellulardegradationUptake fromperitubularbloodEmmanouel DS et al.,1980
  5. 5. Increased Plasma HormoneConcentrations• Reduction of renal mass result in decrease inthe metabolic clearance• If catabolic mechanisms differ, alteration inthe relation between biologically active andinactive hormone fragments occur• Concentrations of certain prohormones areelevated e.g., pro-insulin, pro-IGF1AAvner Paediatric Nephrology 6th Ed
  6. 6. • Extrarenal hormone elimination may also bereducede.g., degradation of insulin in skeletal muscle tissueis diminished• Hypersecretion of various hormones orhormone binding proteinsAppropriate response to secretory stimulie.g., PTHWithout an apparent homeostatic signale.g., prolactin
  7. 7. Decreased Plasma HormoneConcentrations• The reduction in functional renal mass maincause for decreased levels of hormonesproduced by thekidneye.g., Erythropoietin, 1,25-(OH)2 vit D3• Uremic milieu may suppress the production ofhormonese.g.,Intracellular phosphate accumulationmay inhibit 1α hydroxylase
  8. 8. • Extra renal hormones decreased when thehormone-producing gland is the final effectororgan of complex hormonal axise.g., Testis-testosterone, Ovary-estradiolDirect toxic damageInsufficient stimulatory input from superior part ofthe hormonal axisHypo responsiveness of the gland
  9. 9. Disorders of Hormone ActionHormone Binding to Plasma Proteins– Excessive concentrations of several insulin-likegrowth factor (IGF) binding proteins– Binding proteins can compete for the hormonewith target organ receptorse.g., Reduced somatomedin bioactivity in thepresence of normal total serum IGF
  10. 10. Disturbed Activation of Prohormones– Peripheral conversion of T4 to tissue active T3 isimpaired• Low T3 syndrome– Chronic Met acidosis and IL-6 downregulatesperipheral conversion of T4 to T3– Uremia blunt bioavailability and cell uptake ofThyroid hormone leads to thyroid resistance stateWiederkehr MR et al., 2004; Torpy DJ et al., 1998
  11. 11. Alterations of Target Tissue Sensitivity• Reduced cellular receptor activation due tothe diminished receptor abundance• Presence of inhibitory substances• Accumulation of molecules inhibitinghormone-receptor interaction• Defects of hormone receptor complexdependent intracellular signallinge.g., Insulin and GH resistance in uraemiaSmith D, Defronzo RA et al., 1982; Schaefer F et al 2001

×