Effects of dietary caloric restriction and aging on thyroid hormones of rhesus monkeys

• Published in: Hormone and metabolic research Vol. 34; no. 7; p. 378
• Main Authors: Roth, G S, Handy, A M, Mattison, J A, Tilmont, E M, Ingram, D K, Lane, M A
• Format: Journal Article
• Language: English
• Published: Germany 01-07-2002
• Subjects: Aging - physiology; Animals; Caloric Restriction; Diet; Female; Macaca mulatta; Male; Thyroid Hormones - blood; Thyrotropin - blood; Thyroxine - blood; Triiodothyronine - blood
• ISSN: 0018-5043
• DOI: 10.1055/s-2002-33469

Plasma levels of thyroid hormones - triiodothyronine (T 3 ), thyroxin (T 4 ), and thyroid-stimulating hormone (TSH) were measured in male and female rhesus monkeys (Macaca mulatta) fed either ad libitum or a 30 % calorie-restricted (CR) diet (males for 11 years; females for 6 years). The same hormones were measured in another group of young male rhesus monkeys during adaptation to the 30 % CR regimen. Both long- and shorter-term CR diet lowered total T 3 in plasma of the monkeys. The effect appeared to be greater in younger monkeys than in older counterparts. No effects of CR diet were detected for either free or total T 4, although unlike T 3, levels of this hormone decreased with age. TSH levels also decreased with age, and were increased by long-term CR diet in older monkeys only. No consistent effects of shorter-term CR diet were observed for TSH. In the light of the effects of the thyroid axis on overall metabolism, these results suggest a possible mechanism by which CR diets may elicit their well-known beneficial 'anti-aging' effects in mammals.