Abstract
Studies on the indirect effects of ultra violet light on growth, and its therapeutic action in rickets and tetany in children have received new impetus recently from the independent observations of Hess and Weinstock 1 , and of Steenbock and his collaborators 2 that diets which are deficient in certain respects may be made complete by irradiation with light of short wave lengths, or by the addition of certain irradiated substances, such as cholesterol.
The light of the quartz mercury vapor lamp has been found to have definite secondary effects upon some of the endocrine tissues, also, producing a notable hypertrophy of the hypophysis and the (external) parathyroid glands of normal rabbits 3 . The question arises whether the affected glands mediate some of the metabolic effects ascribed to the radiations, and whether irradiated food materials, which appear to have effects similar to those of ultra violet light on growth and in disturbances of calcium and phosphorus metabolism, also act by a specific stimulation of certain endocrine glands.
In these experiments we fed Norwegian cod liver oil, or irradiated cholesterol, to adult male rabbits for periods of several weeks, and at autopsy compared the weights of certain of their endocrine organs with those of normal rabbits, and of rabbits irradiated with a quartz mercury vapor lamp over similar periods of time.
Experiments I and II. Cod liver oil.
In addition to their regular diet, two groups of 6 and of 10 normal adult male rabbits (one group studied in April, the other in December) received 2 to 4 cc. of cod liver oil daily for periods of 3 to 4 weeks. Two groups of 17 and 14 normal rabbits, from the stock of Drs. Brown, Pearce, and Van Allen, examined coincidently with the experimental animals, served as controls.
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