Familial combined hyperlipoproteinemia. Evidence for a role of growth hormone deficiency in effecting its manifestation.

Hyperlipidemia associated with an isolated deficiency of growth hormone was investigated in 10 subjects with hypercholesterolemia consistently present over a 10-yr period. 8 of these 10 had serum triglyceride concentrations greater than 185 mg/dl. 13 growth hormone-deficient patients with normal serum lipids, 28 age-matched controls, and 6 families possessing both growth hormone-deficient and hormonally normal members were also studied. Hyperlipidemia occurred with growth hormone deficiency only in families in which hormonally normal subjects likewise exhibited hyperlipidemia. However the elevation of serum lipids, particularly cholesterol, was invariably greater in the growth hormone-deficient members of these families. Studies were most consistent with the classification of this trait as familial combined hyperlipoproteinemia. Basal serum concentrations of insulin, glucose, and free fatty acids were similar in all groups. After oral glucose (1.5 g/kg of body wt) both hyperlipidemic and normolipidemic dwarfs exhibited a similar degree of glucose intolerance associated with insulinopenia. Sensitivity to insulin, assessed after the intravenous injection of insulin (0.05 U/kg of body wt), increased and was virtually identical in the two dwarf groups. Administration of 5 mg of human growth hormone twice a day for 1 wk to five subjects did not alter serum lipid patterns. The data provide no conclusive evidence concerning a direct effect of growth hormone deficiency on hyperlipoproteinemia. We postulate that in some individuals growth hormone deficiency may unmask an underlying defect in lipoprotein metabolism.