Effect of Pyrogen on Blood Levels of Pituitary Trophic Hormones. Observations of the Usefulness of the Growth Hormone Response in the Detection of Pituitary Disease

The effect of pyrogen on plasma GH, LH, TSH and cortisol levels has been measured in 17 normal subjects, 13 patients with pituitary disease, and 3 patients with primary hypothyroidism. In 16 of the 17 normal subjects the plasma GH was greater than 10 mμg/ml at some time during the test, and plasma cortisol level increased by at least 5 mμg/100 ml. The GH response was not suppressed by glucose infusion in 2 subjects. Pyrogen did not cause an increase in LH or TSH in any subject. The TSH levels in 3 patients with primary hypothyroidism decreased 1 hr after pyrogen at the same time that plasma GH levels were elevated. These data show that pyrogen is not a nonspecific stimulus to the hypothalamic-pituitary system causing release of all polypeptide hormones. Growth hormone levels of greater than 10 mμg/ml after pyrogen occurred in only 1 of 13 patients with pituitary disease. In 8 of the 13 patients, however, the plasma cortisol increment was greater than 5 μg/100 ml. Thus, measurement of plasma GH in response to pyrogen increases the sensitivity of the test for the detection of pituitary disease.