Lemmings into the sea or back across the bridge? The fate of albumin in nephrotic syndrome.

An intact glomerular filtration barrier is essential for maintaining plasma albumin levels. However, the capacity of the proximal tubule to reabsorb filtered albumin and the subsequent fate of this protein are hotly debated. Weyer et al. find that knockout of megalin and cubilin receptors in a nephrotic mouse model causes no further reduction in plasma albumin levels, suggesting that albumin retrieval by the proximal tubule does not contribute significantly to albumin homeostasis.