Unresponsiveness to exogenous TSH in obesity
Schmitt, T.; Luqman, W.; McCool, C.; Lenz, F.; Ahmad, U.; Nolan, S.; Stephan, T.; Sunder, J.H.; Danowski, T.S.
International Journal of Obesity 1(2): 185-190
1977
ISSN/ISBN: 0307-0565 PMID: 82548 Document Number: 117626
Thyroidal and related indices were measured in 275 obese patients. Serum protein-bound I was within the normal range for all but 1 patient who had myxoedema. With the exception of that patient, this was also true of serum total triiodothyronine and thyroxine. Other tests included the 24-h thyroidal uptake of 131I, the V-P interval of ankle reflex time and serum cholesterol. In 126 of the patients, the responses of the 24-h thyroidal 131I uptake to subcutaneous thyrotropin were studied. In 22% of the patients, the basal thyroidal 131I uptake was less than 10%. In 18% of them, 131I uptake did not increase after thyrotropin. The V-P interval of the ankle reflex was prolonged in 20% of the patients. In 12% serum cholesterol exceeded 274 ng/100 ml. Multiple abnormalities of these 4 indices were recorded in 24 of the 275 patients. Low basal thyroidal 131I uptake and failure of exogenous thyrotropin to increase 131I uptake were not more frequent in the older patients. The frequency of a basal 131I uptake of 10% or less at 24 h was highest (52%) in those patients with the greater excesses of bodyweight. It seems that in some obese patients, loss of response to thyrotropin could contribute to the obesity.