The area of 2-[125I]iodomelatonin binding in the pars tuberalis of the ground squirrel is decreased during hibernation

Abstract

Quantitative receptor autoradiography was used to analyze 2-[125I]iodomelatonin binding sites in the brains of golden-mantled ground squirrels (Citellus lateralis). Specific binding appeared to be discretely localized to the pars tuberalis region of the pituitary that surrounds the medial basal hypothalamus. The total area of binding was significantly decreased in brains of hibernating squirrels as compared to those of awake, euthermic animals. These findings support a role for melatonin receptors of the pars tuberalis in seasonal behavior.