LIPIDS AND APOLIPOPROTEINS IN GROWTH HORMONE-DEFICIENT CHILDREN DURING TREATMENT

The role of growth hormone (GH) in regulating the transport of plasma lipoproteins has not been clearly defined, but past studies suggest that GH may influence cholesterol levels. This protocol was designed to evaluate possible changes in lipid and apolipoprotein status in GH-deficient children and children with neurosecretory dysfunction (NS) before GH therapy and at intervals after GH therapy was started. Twenty children with classic GH deficiency were evaluated, and 28% were hyperlipidemic at the onset of the study. Seven children were evaluated in the NS group, and only one (14%) showed an elevated total cholesterol (TC) greater than 200 mg/dL. The mean TC for all the GH-deficient children was elevated above the normal range, but not for the NS group. The mean apolipoprotein (apo) C-III level and its heparin-precipitated fraction (HP) were also elevated in the GH-deficient group, hut only the apo C-III HP was elevated in the NS group. A standard replacement dose of recombinant methionyl GH was used; and therapy had no significant effect on TC or triglyceride (TG) levels. Apo C-III HP, a marker of hypertriglyceridemia, increased after the start of therapy, hut no other lipoprotein levels changed significantly in the GH-deficient group. No changes were seen with treatment in the NS group. The longitudinal design of this study allowed demonstration of the later changes in the apolipoproteins and the presence of a distinct subset of patients with both GH deficiency and hypercholesterolemia. This study supports the role of GH in modulating lipid metabolism.