Abstract
In the course of certain experiments upon sensitiveness of partially nephrectomized rats to parathyroid extract, an opportunity was offered to ascertain whether the administration of this hormone over shorter or longer periods leads to a reduction in the size of the parathyroid glands. It is a commonly held belief that substitution therapy brings about functional atrophy of the endocrine glands producing the secretion. In the case of the parathyroids, Jaffé and Bodansky 1 have reported that in dogs, the size of the parathyroid was reduced from one-third to one-half of that usually found; and that there were microscopic evidences of atrophy after acute or chronic experimental hyperparathyroidism. However, they did not weigh or measure the glands, and it seemed desirable to obtain more precise information on the subject.
White and hooded rats were maintained on a standard diet. 2 Parathyroid extract (Lilly) was given by intraperitoneal injection in total doses ranging from 200 to 2150 Hansen units over periods of from 3 to 51 days. The combined volume of the parathyroid glands, after short fixation in Zenker, was measured from serial sections. 3 Determinations were made on 4 groups of rats: Group (I) Normal, untreated controls. Group (II) Normals, treated with parathyroid extract. Group (III) Partially nephrectomized, untreated rats. Group (IV) Partially nephrectomized rats, injected with parathyroid extract.
The individual data are shown on the scatter chart, and the mean values in the various groups are presented in Table I.
It is obvious that the injection of parathyroid extract, even in large closes, does not bring about an involution of the normal glands, nor does it prevent the hyperplasia which follows partial nephrectomy.
We are greatly indebted to the Eli Lilly Co. for the parathyroid extract used in these experiments.
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