[Serum growth hormone levels in Hunter's syndrome]

Serum growth hormone (GH) levels were measured in 3 brothers with Hunter syndrome. The secretion of GH was studied by means of insulin (ITT), glucose (GTT), lysine-vasopressin (LVP), and L-Dopa administrations. Mean basal GH levels during the 4 tests were high (x = 14.2 ng/ml) in all cases. In the ITT and LVP tests, GH responses correlated positively with the patients' ages. Contrarily, after L-Dopa administration, GH elevations were normal in the two younger and absent in the oldest case. During GTT, GH levels were suppressed in all cases as expected. Basal cortisol and prolactin serum levels during the tests were normal. In order to clarify these data, GH levels were then determined during 120 min. (20-20 min.) under basal conditions. The means (+/- SD) of GH were 178 +/- 0.15; 4.42 +/- 2.47; and 2.30 +/- 0.71, for cases 1, 2 and 3, respectively (normal values 0-5 ng/ml). Basal somatomedin-C levels were in low-normal ranges. As patients were not undernourished and albumin levels were normal, a slight dysfunction of hypothalamic-pituitary-GH-somatomedin-C axis might occurred in these cases. The hypothesis here offered is that a primary sub-production of somatomedin-C, mainly by liver and kidneys, could be present in Hunter syndrome. This situation would lead to normal-high GH serum levels, as seen in the present cases. GH serum measurements in Hunter syndrome were not documented previously.