Age-related changes in central nervous system beta-endorphin and ACTH.

Aging is associated with alterations in mood, thermoregulation, pain threshold, and stress response. Because these functions may be modulated by endogenous opiates, we measured immunoreactive ACTH with beta-endorphin in discrete brain areas and pituitary glands from rats aged 6 weeks (young), 6 months (mature), and 20-24 months (senscent). Beta-Endorphin and ACTH declined significantly with aging in the hypothalamus and corpus striatum. Beta-Endorphin and ACTH increased in the frontal lobe during early life; however, no change was noted after maturity. A discordant response with age was noted in the pituitary in that (ACTH did not change, while beta-endorphin increased early in life without change after maturity. Cerebellar tissue exhibited no immunoreactive ACTH or beta-endorphin. Age-related changes in brain and pituitary beta-endorphin and ACTH must be considered in the evaluation of the physiological aging process and when comparing studies of these neuropeptides.