Labels:text | screenshot | black | black and white OCR: yroid Hypothalamic disease is a rare cause of th evels are failure. In such instances, circulating T4 TSH is low, T3 may be normal or low, and basa TSH normal or low (Fig. 15.32). The pituitary uggish and response to exogenous TRH is usually s higher thandelayed, and values at sixty minutes are tion. at twenty minutes after TRH administra