[Familial nephropathy in cocker spaniels]

In 21 normal dogs of different breeds and ages the number of nephrons was calculated from paraffin sections in comparison with a maceration method. With these methods the number of glomeruli x 1000 per kidney appeared to be 502 +/- 213 and 515 +/- 230 respectively. The histological method appeared to be acceptable for the determination of the number of glomeruli in incomplete kidneys. The examined Cocker Spaniels consisted of 5 animals without renal problems for control and 21 animals with nephropathy: 12 of 1-2 years, 6 of 4-6 years and 3 of 9-10 years old dogs. As indication for the present number of nephrons the glomeruli were counted in bands of whole cortex with a width of 1 mm. The number of glomeruli per band of cortex in the nephropathic Cocker Spaniels (15.0 +/- 3.0) was not drastic lower than those of the normal Cockers (20.8 +/- 2.5) and of 7 normal adult dogs of different breeds (17.2 +/- 2.2). On pathological examination the nephropathic kidneys showed a membranoproliferative-sclerosing glomerulonephritis with extra-capillary reaction leading to glomerular obsolescence. The animals showed evident proteinuria and final renal insufficiency. It was concluded that the pathogenesis of the familial nephropathy in this breed will not be caused by cortical hypoplasia, but by a primary glomerulopathy.