Nephrotic syndrome is associated with abnormal regulation of renal water excretion .
To investigate the role of collecting duct water channels and solute transporters in this process, we have carried out semiquantitative immunoblotting of kidney tissues from rats with adriamycin -induced nephrotic syndrome. Inner medullary expression of the descending limb water channel, aquaporin-1, was not significantly altered, pointing to a selective effect on the collecting duct. The extensive down-regulation of aquaporin and urea transporter expression may represent an appropriate renal response to the extracellular volume expansion observed in nephrotic syndrome, but may occur at the expense of decreased urinary concentrating and diluting capacity.