Differential Effects of Stress on Release of Thyroid-Stimulating Hormone in Young and Old Male Rats

Abstract
In response to the stress of serial bleeding, ether exposure, or physical restraint, serum TSH [thyrotropin] was depressed more quickly and to a greater extent in young than in old male rats. These results suggest that the hypothalamo-hypophyseal mechanisms which mediate inhibition of TSH release are less sensitive in old than in young male rats.