Solitary Kidney in a White Rat

Abstract

The condition known as solitary kidney, although rare, has been frequently reported in man, in which it is best known (Messing and Ashley-Montagu, Anat. Record, 53: 173-175, 1932; Kelly and Burnam, Diseases of the kidneys, ureters and bladder, New York, Appleton, vol. 2, pp. 308-311, 1914; and others). In cases of solitary kidney, the reproductive system is often abnormal, usually unilaterally deficient, not surprising in view of the utilization of Wolffian and Mullerian ducts in its formation. For examnle, the seminal vesicles, ejaculatory ducts, ductus deferentia, uteri, and fallopian tubes frequently are partially or completely absent (on one side) in cases of solitary kidney. The vagina may also be lacking. Occasionally, both a kidney and its associated adrenal gland are absent. In 153 cases of solitary kidney, both kidney and ureter were absent according to Polack (These de Bordeaux, No. 64, 1909). He reported 20 other cases in which only the kidney was absent, and he found maldevelopment of sexual organs associated with solitary kidney in 41 cases and missing adrenals in 25 cases. Most of these abnormalities were in males. Kelly and Burnam (loc. cit.) mention the size of the solitary kidney as often in excess of usual dimensions. A male white rat, Rattus norvegicus, found among 400 rats used in the general zoology course at the University of Illinois, lacks a right kidney. The left is slightly longer than others examined and is notably larger in its other dimensions (appearing to be greatly swollen). The right renal artery and vein are possibly lacking, although a tiny vein extends to fatty tissue situated approximately where the kidney ordinarily would be. No right adrenal was observed. The reproductive system appears, grossly, to be normal; a ductus deferens is present on each side. The bladder has no apparent malformation inside or out, and the right ureter extends anteriorly to the area where the kidney would ordinarily lie. The connection of ureter with bladder is obscured by adipose tissue, as is its anterior termination as a tiny tube in a plexus of tiny blood vessels. The abnormal rat is preserved as an alcoholic specimen (Univ. Illinois 29429) in the Museum of Natural History.