The role of T3 and its receptor in efficient metabolisers receiving very-low-calorie diets.

Obese patients taking a 1.34 MJ/day formula diet showed a steady decline in the rate of weight loss after several weeks and this was associated with a fall in RMR, serum T3 levels and the number of T3 receptors on peripheral lymphocytes. The addition of T3 (60 micrograms/day) to the dietary regime produced a significantly greater weight loss by the 12th week. Analysis of individual thyroid hormone levels revealed those patients taking the T3 tablets who achieved the greatest weight loss had the lowest serum T3 levels but the greatest suppression of serum T4 values. The serum T3 levels in the T3 treated subjects were negatively correlated with the lymphocyte rece 12th week. Analysis of individual thyroid hormone levels revealed those patients taking the T3 tablets who achieved the greatest weight loss had the lowest serum T3 levels but the greatest suppression of serum T4 values. The serum T3 levels in the T3 treated subjects were negatively correlated with the lymphocyte rece 12th week. Analysis of individual thyroid hormone levels revealed those patients taking the T3 tablets who achieved the greatest weight loss had the lowest serum T3 levels but the greatest suppression of serum T4 values. The serum T3 levels in the T3 treated subjects were negatively correlated with the lymphocyte receptor capacity. It is postulated that the fall in the number of T3 receptors is the primary event leading to the observed serum hormone level changes in the T3-treated patients.