TSH response to TRH in substantial obesity

TSH response to TRH stimulation was studied in 40 non-obese control females and in 40 obese female subjects 40-148 per cent in excess of their ideal weight prior to receiving dietary advice. One patient was found to be hypothyroid and was excluded from further study. There was no significant difference between the basal serum TSH concentration in the subjects and controls. Obese subjects however had significantly greater serum TSH concentrations at 20 and 60 min following TRH stimulation. The implciations of these findings are at present unexplained.