Studies on the Mode of Action of Irradiated Ergosterol

In the first paper of this series (1), we reported that the administration of adequate doses of irradiated ergosterol to normal individuals resulted in definite alterations in the fecal and urinary excretion of calcium and phosphorus. These changes consisted in a gradual fall in the fecal excretion and a gradual rise in the urinary excretion of both elements with little effect on the total balances of either. These findings are best interpreted as signifying increased absorption from the gastro-intestinal tract without an accompanying increased body retention. The fact that irradiated ergosterol acts as a curative agent in calcium deficiency diseases such as rickets and osteomalacia indicates that an increased retention of calcium and phosphorus must take place when it is administered to individuals with such diseases. In order to determine what changes occur in the calcium and phosphorus metabolism of individuals with calcium deficiency diseases when irradiated ergosterol is administered, two such patients were studied in an effort to ascertain whether the action of irradiated ergosterol was in any way different from that which we had observed in normal individuals.