TRH and hypothyroidism: One year prior to her visit, she was diagnosed with severe adult GHD and secondary hypothyroidism due to low levels of both TSH and free thyroxine (T4) [10, 11], and insufficient elevation in GH and TSH levels following intravenous administration of 100 μg of GH-releasing peptide-2 (GHRP-2) or 200 mg of thyrotropin releasing hormone (TRH) (Supplemental Table 1).