Lymphocyte thyroid hormone receptors in obesity

Area of Science:

• Endocrinology
• Metabolic Research

Background:

• Obesity is often associated with difficulties in weight loss.
• Thyroid hormone resistance is a potential factor in some obese individuals.

Purpose of the Study:

• To investigate triiodothyronine (T3) receptor characteristics in obese patients.
• To determine the effect of severe caloric restriction and T3 supplementation on T3 receptor capacity.

Main Methods:

• Studied T3-receptor characteristics in circulating mononuclear cells of obese patients and non-obese controls.
• Monitored receptor capacity changes after 12 weeks on a 1.34 MJ (320 kcal)/day formula diet, with some patients receiving additional T3 (60 micrograms/day).

Main Results:

• Obese patients had lower T3 receptor capacity than controls, though not significantly.
• A significant fall (P<0.01) in T3 receptor capacity was observed in obese patients after 12 weeks of severe dietary restriction.
• T3 supplementation alongside the formula diet led to a further decrease in receptor numbers.

Conclusions:

• Severe dietary restriction significantly reduces T3 receptor capacity in obese individuals, contributing to a lower metabolic rate.
• These alterations in T3 receptor characteristics may partly explain the observed resistance to thyroid hormones in obesity.