The Iodine Metabolism of Drosophila Gibberosa Studied by Means of Radioiodine I 131

Abstract

I131 was made available in the food of D. gibberosa and Geiger counts made of the various dissected tissues. X-ray film was also exposed to paraffin sections of larvae. In larvae fed on the radioactive food I is concentrated in the skeletal parts, 72.7% of the radioactivity being in the skin. No concn. of I131 appeared in any of the larval endocrine structures. In the pupal period, 85% of radioactivity was in the puparium and 14.9% in the pupa[long dash]possibly in the pupal skin. There was no significant radioactivity in any dissected tissues of adults. When adults were fed radioactive food, the highest % of radioactivity was found in the exoskeleton. Expts. with cleaned skins and with molting larvae indicate that a genuine metabolic process and not direct uptake of radioactive I through the skin is involved.