Physical-chemical changes of the blood in thyroidectomized guinea pigs.

Abstract

As far as we have been able to learn, no studies have been made of the surface tension of the blood in thyroidectomized animals. In the course of a series of experiments it became essential to study the surface tension of the plasma of such animals.

We removed the thyroids of a number of guinea pigs and determined the surface tension of the plasma at various periods after operation.

We used the DuNouy Tensiometer for making surface tension determinations. The animals were bled from the carotid artery through a cannula into tubes containing one per cent sodium oxalate. One part of oxalate solution to nine parts of blood was used throughout the entire series. Several experiments were made to determine the effect of different quantities of oxalate solution, and these showed that, within reasonable limits, dilution of blood with varying quantities of oxalate did not appreciably alter the surface tension.

In thyroidectomized animals we found a rise in the surface tension of the plasma, progressively increasing with the longer post-operative period. This rise reached its maximum in from twenty-two to twenty-eight days.

Plasma obtained from animals six and tlhirteen days after operation showed no appreciable increase; we can therefore eliminate the operative procedure as a factor in the changed SUP face tension. On the eighteenth day after operation the increased surface tension lbecam evident. From the eighteenth to the twenty-eighth day there is a distinct increase in the number of animals showing high surface tension. The average surface tension of all thyroidectomized animals on or after the eighteenth day was 57.7 dynes; the average surfa'ce tension of the corresponding normal animals was 53.8 dynes. Thus the plasma from sixteen out of twenty-seven operated animals was found to be albove 55.4 dynes; on the other hand 23 out of 26 normal plasmas were below this figure.