Abstract
There is evidence from human pathology that renal disease is frequently associated with parathyroid enlargement. Renal lesions have been found to accompany hyperplasia or tumors of the parathyroids in over 50% of the reported cases of osteitis fibrosa, 1 and parathyroid enlargement has been demonstrated in various forms of chronic renal disease 2 , 3 , 4 and in renal dwarfism. 5 , 6
The nature of this relationship is not well understood and it seemed of interest to approach the problem experimentally. In this brief report, it will be shown that significant increase in the volume of the parathyroids may be brought about in rats by experimentally reducing the amount of functional renal tissue.
Healthy white rats, weighing from 150 to 250 gm., and maintained on a mixed diet were used for the experiments. One kidney was removed through a lumbar incision, and a considerable portion of the opposite kidney was destroyed by thermo-cautery in 2 operations.
The chief symptoms noted were drowsiness, roughness of the hair and loss of appetite. Although 3 of the rats showed a transient gain of weight after the second cauterization, the weight later remained stationary or declined progressively.
At autopsy, the parathyroids with attached thyroid tissue were fixed in Zenker's fluid, and serially sectioned at 10μ. Their volume was determined by multiplying the combined areas of the section, as obtained with the planimeter from drawings projected at known magnification, by the thickness of the section. The volume was calculated for 100 gm. of rat. Since all of the operated rats lost weight before death, the calculations were based upon the “normal” weight at time of death as estimated from Donaldson's tables, and not upon the actual weight.
The operated rats fall into 2 groups according to the time of survival.
Get full access to this article
View all access options for this article.