Effect of antidiuretic hormone to the connective tissues of rat renal papilla

Abstract

We studied a strain of rats with congenital diabetes insipidus homozygote (DI). The collecting tubules could not concentrate urine. Electron microscopy shows cytoplasmic lesions, vacuoles, swelling and degenerating mitochondria in the collecting tubule cells. Heterozygous animals are similar to the normal animals and rarely show the above described lesions. The connective tissue mucopolysaccharide (MPS) in the renal papilla of normal rats stains more intensely with Alcian Blue-PAS than comparable tissue from DI rats. After vasopressin was given daily to the DI rats for a period of more than three weeks, the animals present a normal water intake, an increase in urine osmolality and an increase in MPS in the connective tissue. The cytoplasmic lesions in the collecting tubule cells also disappear. Thus, it seems reasonable to relate the morphologic changes of DI rats to a lack of appropriate ADH activity. Apparently, ADH causes alteration in the polymeric state of the MPS in connective tissue of the papilla and thereby presumably induces changes in permeability.