Pituitary function and growth hormone dynamics in acromegaloidism.

Acromegaloidism is a condition which resembles acromegaly by its clinical manifestations but is not due to pituitary or hypothalamic dysfunction. Twenty patients were diagnosed as having this disorder and the results from studying growth hormone (GH) responses in 15 patients (11 women and four men) were included in this report. Clinical manifestations closely resembled those of acromegalics, including history of progressive changes, acral enlargement, visual disturbances, abnormal visual fields in four patients, and sella turcica enlargement in two patients. The glucose tolerance test (GTT) was abnormal in 12/15 patients, 13/15 were > 10 percent obese, 8/15 had hypertension, 7/15 had large-statured relatives, but lactorrhea was absent in all patients. The mean serum GH concentration was 2.2 ng/ml, which suppressed to 0.6 ng/ml during the GTT; increased to 24 ng/ml during hypoglycemia; and increased to 10.3 ng/ml after L-dopa ingestion. Other pituitary hormones (LH, FSH, TSH, prolactin), the metyrapone test, 24-hour random and nocturnal sleeping GH concentrations were normal. These GH values and responses helped to differentiate acromegaloidism from treated and untreated acromegaly. The pathogenesis of acromegaloidism was not determined, but somatomedin studies may prove helpful in further defining this disorder.