It is good to see very detailed and specific research into the effects of thyroid hormones. We need this in order to be able to explain the impact of inappropriate levels of thyroid hormones. When we see symptoms dismissed, knowing precisely how the symptom can be caused should be a huge advantage.
Thyroid hormones and browning of adipose tissue
Juliane Weiner, Mohammed Hankir, John T. Heiker, Wiebke Fenske, Kerstin Krause,
• TH play a pivotal role in the regulation of thermogenesis.
• TH effectuate BAT thermogenesis and BeAT formation by peripheral and central effects in rodents.
• Activation and recruitment of BAT and BeAT represents a promising therapeutic approach to combat obesity.
Thyroid hormone (TH) disorders are associated with profound changes in whole body energy metabolism. A major TH target is thermogenic brown adipose tissue (BAT), which can be stimulated directly through thyroid hormone receptors (TRs) expressed in brown adipocytes and indirectly, through TRs expressed in hypothalamic neurons. White adipose tissue (WAT) adopts BAT characteristics by a diverse range of stimuli in a process referred to as browning. It is now understood that TH also induce WAT browning through peripheral and central mechanisms. In this review, we discuss evidence from animal and human studies that TH disorders are associated with changes in both BAT thermogenesis and WAT browning, thereby influencing body temperature and body weight regulation.
[ Edited to add:
This link has a picture showing where most human brown adipose tissue is - near the thyroid. I found the location as seen in a thermograph picture stunning - it is impossible to see it and ignore the proximity to the thyroid gland.
That image comes from this article which might also be of interest: