Kidneys and cobalamin (B12):
The information goes back decades, although researchers still are trying to better understand the connection between kidneys and cobalamin. This is one of the issues about which mostly questions remain.
http://www.metabolismjournal.com/art...00661/abstract
This is very interesting. Maybe one of our more brilliant members can shed some light.
From:
Megalin is essential for renal proximal tubule reabsorption and accumulation of transcobalamin-B12
Quote:
|
Megalin is important for normal uptake of filtered TC-B12 and accumulation of the vitamin. In megalin-deficient mice, increased urinary excretion of both TC (Fig. 2) and vitamin B12 (Table 1) was observed. Urinary B12 concentration was increased approximately fourfold despite significant lower serum B12 levels. As a result, urinary B12 clearance was increased ~28-fold in megalin-deficient mice. Furthermore, no vitamin B12 could be identified by immunocytochemistry in the proximal tubules from megalin-knockout mice, indicating defective cellular uptake of the vitamin (Fig. 3). Little or no TC was identified in urine from control littermates (Fig. 2), whereas cellular B12 uptake was evident in proximal tubules (Fig. 3). The defect in vitamin accumulation in megalin-deficient mice was further substantiated by the determination of vitamin B12 concentration in kidney cortical tissue from two megalin-knockout mice, showing a fourfold reduction compared with normal controls (Table 1).
|
rose