Intramembraneous Particle Cluster and Cytoplasmic Vesicles in Mice with Nephrogenic Defects of Urinary Concentration

摘要

Previous studies on mice with severe nephrogenic diabetes insipidus (NDI) had suggested that their urinary concentrating defect was due to an inability to increase the water permeability of the collecting duct system. Other studies, utilizing vasopressin-sensitive amphibian epithelia, have reported the appearance of intramembranous particle (IMP) clusters in luminal membranes, possibly arising from cytoplasmic vesicles, during states of increased water permeability. The present study was designed to help characterize at the cellular level, the urinary concentrating defect of NDI mice. The present study provides evidence that the defect in urinary concentrating ability found in NDI mice, both Severe and Nonsevere, may be partly due to a lack of IMP clusters, which probably reflects deficient vasopressin-induced water permeability of the collecting duct system. This defect is probably not identical to the defect(s) previously observed in CBA Os/+ mice.