The Intravenous Administration of Irradiated Ergosterol. ∗

Abstract

This investigation was begun in the hope that the intravenous administration of ergosterol might throw some light on the mechanism of its action, if it could be shown to be effective by this method. Normal dogs of 10 to 12 kilos weight were selected and confined to a stock diet of ground beef heart and Puppy Meal, 3:1. Ten animals have now been studied. Routine determinations of calcium and inorganic phosphorus were made. Figure 1 shows the results on one animal, which is fairly typical of the series. After a short period of preliminary observation, injections were begun of ergosterol in corn oil. This oil alone, in amounts up to 15 cc. does not produce any of the observed effects. In the illustrative case. approximately 20 mg. were administered daily during 2 weeks. The calcium concentration was increased, but there were pronounced fluctuations for which no explanation can be offered at present. During 10 days, the animal gained weight rapidly and became extraordinarily active. During this time also, there were pronounced fluctuations in the concentration of inorganic phosphorus, but the average level was unchanged. At the end of this period it became apparent that the calcium concentration was decreased almost to the original level; so the daily dose was increased to 30 mg. The result was a second increase in calcium to almost 16 mg. at the end of another week. The dose was now increased to 50 mg. On the 25th day after the first administration, the calcium concentration was increased to almost 19 mg.; at this time the phosphorus had fallen to 4.7 mg. The dog had now begun to lose weight and had become less active. At the termination of the observation, post mortem examination of various organs, particularly of the parathyroids, will be made.