African Journal of Internal Medicine

African Journal of Internal Medicine ISSN: 2326-7283 Vol. 11 (4), pp. 001-007, April, 2023. © International Scholars Journals

Full Length Research Paper

Revisiting the relative contributions of sympathetic and thyroidal actions to adaptive thermogenesis in man and animals

Orien L Tulp, PhD, MD, FACN, CNS

College of Medicine and Graduate Studies, University of Science Arts and Technology, Montserrat, British West Indies.  MSR1110. and the Einstein Medical Institute, Florida USA.

Accepted 06 April, 2023 


The processes of adaptive thermogenesis in response to changes in diet and environment have been reported in rodent species as contributors to mechanisms of energy balance and expenditure for the past four decades, but their relevance in humans remains speculative, despite the common observation of active brown adipose tissue in both man and animals. To determine the relative contributions of the two primary hormonally mediated systems in adaptive thermogenesis during over nutrition via the Cafeteria feeding regimen (Café), the relative contributions to the sympathetic and thyroidal mechanisms were estimated by measures of serum T3, Urinary Vanilmandelic acid (VMA) and resting thermogenesis (VO2) and before and after sympathetic ablation with α-methylparatyrosine (αMPT) in congenic lean male LA/Ntul//-cp rats.. The Café diet resulted in significant elevations in T3, VMA, and VO2.  The αMPT resulted in virtual elimination of sympathetic activity as indicated by urinary VMA excretion, but only a partial decrease in VO2, consistent with residual non-sympathetically-mediated contributions. Thus, the results of this study are consistent with both sympathetically mediated short term influences in addition to longer term thyroidally mediated actions on the expression of adaptive thermogenesis during overfeeding in this congenic lean strain of rats.

Key Words:  Nonshivering thermogenesis, obesity, cafeteria feeding, congenic LA/Ntul//-cp rats.