OBSERVATIONS ON THE PINEAL GLAND, THE HARDERIAN GLANDS, THE RETINA, AND THE REPRODUCTIVE ORGANS OF ADULT FEMALE RATS EXPOSED TO CONTINUOUS LIGHT

Abstract

SUMMARY: Harderian gland removal caused enlargement of the uteri of adult female albino rats which were maintained in 14 h light and 10 h darkness/day. Constant light exposure led to regression of the ovaries, adrenal glands and Harderian glands while the uteri exhibited a significant hypertrophic response. None of these changes were affected by surgical removal of the Harderian glands. The eyes and the retinas of albino rats maintained under continuous illumination underwent atrophic changes with the receptor cell elements of the retinas completely disappearing within 9½ weeks. Constant light obliterated the diurnal rhythm in the pineal enzyme, N-acetyltransferase. Neither the activity of pineal hydroxyindole-O-methyl-transferase nor the activity of pineal N-acetyltransferase were influenced by removal of the Harderian glands.