THE EFFECTS OF CONTINUOUS LIGHT OR DARKNESS ON THYROID FUNCTION IN MICE12

Abstract
The effects of continuous light or darkness for 28 days on thyroid activity were studied in 204 albino mice of both sexes. Continuous light induced significant reductions in thyroid wt., thyroid reaction to thiouracil, and thyroid uptake of radioactive I (I131). Continuous darkness produced significant increases in thyroid wt., thyroid reaction to thiouracil, and thyroid uptake of radioactive I. Apparently continuous light depresses while continuous darkness increases thyroid secretion in mice.