How does decreased free heme affect iron uptake into RBC?
Iron uptake is not inhibited
Leads to Sideroblasts (RBC surrounded by iron)
How is Globin translation activated by excess Heme?
Heme binds Heme regulated inhbitor kinase
eIf-2 is dephosphorylated
GTP replace GDP
*Globin translation initiated
What is the general definition of porphyrias?
Increased Heme intermediates either in the liver or BM
Where are acute porphyrias generally found, Liver or BM? What are the main causes of Acute Porphyrias?
Alcohol and drugs (p450)
What is cutaneous porphyria?
Porphyrins taken in a lot of light and causes free oxygen radical damage
What is the result of Acute Intermittent Porphyriaand how is it treated?
More ALA-S1 and PBG because of a lack of PBGD to eventually form Heme.
Less heme formed to inhibit ALA-S1function
*resolve by administering IV hemin to inhibit ALA-S1 production
What causes Porphyria Cutanea Tarda and how is it treated?
Lack of UROD
Increase in uroporIII which undergoes oxygenation from photosensistive porphyrins.
Increased iron overload
**Phlebotomy treats since you remove iron