Influence of Posterior Pituitary Extracts on Sodium Balance in Normal Subject and in Patient with Diabetes Insipidus

Abstract

In the normal subject anti-diuretic extracts of the posterior pituitary cause an increase in the excretion of sodium and chlorine with the result that the balance for these elements becomes negative. 1 , 2 In Fig. 1 we have presented data on a normal subject (male, 25 years old) which shows the same thing. The patient with diabetes insipidus (male, 19 years old), on the other hand, behaves differently. The same dose of posterior pituitary extract as given the normal caused no increase in sodium chloride excretion although a marked anti-diuresis resulted (Fig. 1). The days upon which “Pituitrin” (Surgical, 0.5 cc. twice daily) was administered are indicated in solid black. In the normal subject there was no appreciable reduction in urine volume the rate being about 1.5 liters per day without the extract and 1.2 to 1.4 liters per day when “Pituitrin” was given. In the patient with diabetes insipidus the specific anti-diuretic effect was obvious. The daily urine output was reduced from around 8 to 3 liters per day with a corresponding decrease in the fluid intake.

Both subjects received a constant diet during the period of observations and for several days preceding. The data in Fig. 1 assumes a constant excretion in the stool of the various elements each day. Although we know that this is not absolutely true we have data which shows that the variations are such as to have no influence upon the picture presented here. The urinary excretion in these cases is therefore a good measure of the mineral balance. In the normal it happens that the chlorine does not follow the sodium as closely as it might because this subject had 5 gm. of KCl added to his diet each day and the percentage variation in chloride excretion is consequently less than in sodium excretion, with the same absolute change in both. Unlike the normal the sodium balance does not become negative in diabetes insipidus as a result of “pituitrin” therapy. In this patient it happens that it actually becomes positive, at least for 4 days and although not a constant result in this condition it is frequently the case.