EFFECT OF ULTRAVIOLET IRRADIATION ON THE MAGNESIUM CONTENT OF RATS RECEIVING REFLECTED SUNLIGHT AND A UNIFORM STOCK RATION

Abstract

Experiments to test the theory that rickets is caused by the deficiency in the blood plasma were performed on 2 litters of young rats, 10 in each litter. Of these, 5 in each litter, 10 in all, were irradiated with ultraviolet rays for 3-5 min. for 55 days, while receiving the same food and treatment as the non-irradiated rats. All were kept in cages removed from direct sunlight. At the end of the experiment the rats were cloroformed and the carcasses dried and analyzed. The irradiated rats gained more in wt. than did the non-irradiated; the latter did not quite attain the state of rickets. The most striking and significant finding from analysis was the fact that the Mg content of the irradiated rat carcass and leg bones was a little more than 1/2 as much as that in the non-irradiated rats. The Ca and P content of the irradiated bones was also less than that in the non-irradiated. These findings support the view of Mellanby, Cattaneo, Malcolm, and Forbes as to the importance of Mg in the production of rickets; they also indicate that ultraviolet irradiation prevents rickets, not by increasing Ca but by eliminating Mg and maintaining a proper Ca-Mg-P balance in metabolism.