Absorption of Histamine From the Intestine of the Parathyroidectomized Dog.

In 1912 Carlson 1 described pathological changes in the stomach and upper intestine in dogs which had died as a result of parathyroidectomy. Spadolini 2 has made similar observations, and holds that the condition involves an increased permeability of the intestinal mucosa. He believes that the syndrome which follows loss of the parathyroids may be due, at least in part, to increased absorption of toxic substances produced by proteolytic bacteria. Condorelli 3 has also found changes in the intestinal mucosa following parathyroidectomy, although he does not agree with Spadolini as to their significance.

There is no direct evidence, so far as we know, that loss of the parathyroids facilitates the absorption of any specific substance from the intestine. Histamine is produced there by proteolytic bacteria, and its toxic properties are well known. As shown in the accompanying paper, the mucosa may be rendered permeable to it by relatively mild chemical agents. It seemed possible that a similar change in permeability might occur after loss of the parathyroids, in view of the extensive damage to the mucosa which has been described. If so, some support would be given to the toxemia theory of Spadolini.

Experiments were carried out on 8 dogs, each being used 6 to 8 days after removal of the parathyroids and thyroids. All of the series had shown repeated attacks of tetany. Four additional animals were operated on. Two of these never developed symptoms and were discarded. Two others died under anesthesia before the experiment was completed.

Sodium barbital was the anesthetic employed. With arterial blood pressure and respiration being recorded, ergamine acid phosphate (Burroughs, Wellcome) was introduced into the duodenum, through a tube arranged as described in the accompanying paper. The dosage was 10 mg. per kilo body weight.