Composition of Granules from Kidneys of Rainbow Trout (Salmo gairdneri) with Nephrocalcinosis

Histological sections and isolated granules from kidney tubules of rainbow trout (Salmo gairdneri) with nephrocalcinosis show that the mineral deposits form a network imbedded in a ceroid matrix. The mineral portion, about 80% by weight of the granules, contains 30% Ca, 2.5% Mg, 15% P, and 5% CO3. The matrix is basophilic, sudanophilic and acid fast, is insoluble in lipid solvents but will dissolve in hot 10% NaOH. Key words: nephrocalcinosis, calcification, ceroid, rainbow trout