CALL FOR PAPERS Comparative Genomics Nephron deficit is not required for progressive proteinuria development

Wistar Frömter (MWF) rat represents a genetic model with an inher-ited nephron deficit and exhibits mild hypertension and progressive albuminuria, which is more pronounced in males than females. Pre-viously, we demonstrated in a consomic strain that replacement of a quantitative trait locus on chromosome 6 normalized the nephron deficit and suppressed albuminuria development, suggesting a link between the two findings. Here we tested the role of a second major locus linked to albuminuria in MWF on chromosome 8 and generated the consomic strain MWF-8SHR by transfer of chromosome 8 from spontaneously hypertensive rats (SHR) into MWF. The early onset of albuminuria at 8 wk of age in MWF (50-fold increase compared with SHR) was significantly suppressed in consomic animals, and the development of marked proteinuria at 32 wk significantly diminished. Total nephron number in consomic rats (23,771 1,352) and MWF (27,028 1,322) were similar and significantly lower (36%