STUDY OF PRIMARY HYPERPARATHYROIDISM IN UROLOGY

IV. AN ELECTRON MICROSCOPIC STUDY ON THE KIDNEY IN EXPERIMENTALLY INDUCED HYPERPARATHYROIDISM

Abstract

Since Albright et al. first described in 1929 that the parathyroid hormone increased phosphorus excretion from the kidney, it has been well known that the parathyroid hormone has the direct effect not only on the bone but on the kidney.
In this study, ultrastructural changes of canine kidneys, in which hyperparathyroidism was induced experimentally by means of parathyroid extract injection, were studied using electron microscope.
Because the most prominent changes were observed in the proximal convoluted tubules, it was considered that the parathyroid hormone acts chiefly upon this site in the kidney.
Ultrastructural changes in the proximal convoluted tubules of the kidney in experimentally induced hyperparathyroidism were as follows
1. Tubular lumen was open and the microvilli of brush border were loosely arranged. Cytoplasm of tubular epithelium was often protruded and fell into the tubular lumen. Sometimes fibrillous substance or small spherical bodies, presumably the origin of urinary tract calculi, appeared in the tubular lumen.
2. In the tubular epithelium, vesicles, vacuoles and electron dense bodies including lysosomes were increased in number possibly due to increase of mucopolysaccharide transport by the effect of the parathyroid hormone. Mitochondria were swollen or vacuolized, and decreased in number.
3. Deposition of electron dense substance was found in the basement membrane which increased in thickness. This alteration was considered probably the first evidence of nephrocalcinosis.