Growth hormone (GH) treatment decreases postprandial remnant-like particlecholesterol concentration and improves endothelial function in adult-onsetGH deficiency

Premature atherosclerosis is a clinical feature in adult-onset GH deficienc y. Evidence is accumulating that disturbances in triglyceride metabolism, r eflected by abnormalities in circulating remnant lipoproteins, are associat ed with increased atherogenic potential. In a case-controlled intervention study, we investigated postprandial lipoprotein metabolism using a new remn ant lipoprotein method based : on immunoseparation principle [RLP-cholester ol (RLP-C)]. In addition, we analyzed retinyl eater (RE) analysis in plasma and in Sf < 1000 fraction. Endothelial function was assessed as flow-media ted dilatation (FMD). Eight patients diagnosed with acquired adult-onset GH deficiency and eight controls matched for gender, age, body mass index, an d apolipoprotein (apo) E genotype were enrolled in the study. Oral vitamin A fat loading tests were performed at baseline in both groups and after 6 m onths of treatment with recombinant human GH (rh-GH) in the adult-onset GH- deficient patients. Adult-onset GH-deficient patients had significantly hig her fasting RLP-C, postprandial RLP-C concentrations (plasma RLP-C, 0.29 +/ - 0.14 mmol/L; and incremental area under the curve-RLP-C, 2.13 +/- 1.60 mm ol*h/L, respectively) than controls (0.19 +/- 0.06 mmol/L and 1.05 +/- 0.72 mmol*h/L (P < 0.05), respectively). They also had significantly higher pos tprandial RE in plasma and Sf < 1000 fraction. Treatment with rh-GH signifi cantly reduced postprandial RLP-C concentrations (incremental area under th e curve-RPL-C 0.73 +/- 0.34 mmol*h/L; P < 0.05) but had no effects on the f asting RLP-C concentrations (0.317 +/- 0.09 mmol/L, P < 0.05), or on the po stprandial RE in plasma and in Sf < 1000 fraction. Endothelial function mea sured as FMD was improved from 5.9 +/- 3.3% to 10.2 +/- 4.0% (P < 0.05) in patients treated with rh-GH. It is concluded that patients with adult-onset GH deficiency have increased levels of fasting and postprandial RLP-C and an impaired endothelial funct ion as measured as FMD. Treatment with rh-GH resulted in a decrease of post prandial RLP-C concentration, thereby improving the postprandial atherogeni c lipoprotein profile and improvement of endothelial function, however, the clearance of large chylomicron particles as reflected by RE remained distu rbed.