Thyroid hormone levels related to energy and nitrogen balance during weight loss and regain in adult sheep

• DOI: 10.1530/acta.0.0930440
• Publication Date: 2008-12-15T21:36:12Z
• Authors: J. W. Blum; M. Gingins; P. Vitins; H. Bickel
• Keywords: Overnutrition; Nitrogen balance; Reverse triiodothyronine; Caloric theory

Caloric deprivation (feeding 50 and 25% of the original maintenance requirement for 126 days), followed by overnutrition 133 200% requirement) 37 days, were induced in 7 adult sheep. Before after periods undernutrition animals fasted (total energy withdrawal) 5 days. Energy- nitrogen-balances determined related to concentrations thyroxine (total: T4; free: FT4), 3,5,3'-triiodothyronine T3; free FT3) 3,3',5'-triiodothyronine (reverse T3,rT3). caloric led decreased T3 FT3 levels, increased concentration. was significantly correlated with energy- (r = 0.73 0.71, respectively; P less than 0.001). T4 FT4 behave similar T3, but correlations between levels low. In contrast rT3 during withdrawal overnutrition. After an months, additional fasting days did not increase however, -0.50 -.50, 0.01).