HYPOTHYROIDISM resulting from a lesion of the hypothalamus has been suspected in the past,1 but convincing evidence for this diagnosis could not be presented until the recent preparation of synthetic thyrotropin-releasing factor (TRF) made direct testing of pituitary function possible.2 The patient described below had hypothyroidism and undetectable serum thyrotropin (TSH) levels, with a normal response to TRF.J.L., a 19-year-old man, was admitted to the University of Alabama Hospital on November 10, 1970, with slightly short stature, dry skin and previously diagnosed diabetes insipidus. Gestation, birth and growth to the age of 12 years had apparently been normal. At . . .