Plasma cholesteryl ester transfer protein and lipoprotein levels during treatment of growth hormone-deficient adult humans.
ABSTRACT The incidence of atherosclerosis is increased in growth hormone (GH) deficient-individuals. Nonetheless, the antiatherogenic benefits of GH replacement therapy remain uncertain. In this study the effect of human recombinant growth hormone (hrGH) replacement therapy administered to GH-deficient adults on the plasma cholesteryl ester transfer protein (CETP) concentration and activity was analyzed. These findings were related to changes in the concentrations of the plasma lipoproteins. The hrGH was administered for 12 mon to human GH-deficient patients (n = 13; 8 men, 5 women). During the study plasma lipoproteins were separated by ultracentrifugation, and plasma cholesterol esterification rate (CER), endogenous CETP activity, and CETP concentration were measured. GH replacement therapy transiently (at 3 mon) lowered plasma concentration of CETP and low density lipoprotein-cholesterol (LDL-C) and raised total triglycerides. Furthermore, hrGH permanently increased both the plasma lipoprotein(a) [Lp(a)] concentration, which is known as atherogenic, and the proportion of cholesteryl ester in the high density lipoprotein2 (HDL2) particles, which is potentially atheroprotective. The simultaneous decrease of the plasma CETP and LDL-C concentrations elicited by hrGH indicated a close relationship between LDL metabolism and the regulation of the CETP gene expression. Endogenous CETP activity and the CER were not modified because these parameters are regulated in opposite ways by plasma levels of triglycerides; that is, CER increased and CETP decreased.
Medicina Clínica 01/2003; 120(16):630-637. DOI:10.1157/13046928 · 1.25 Impact Factor
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ABSTRACT: Reduced growth hormone (GH) secretion is observed in obesity and may contribute to increases in cardiovascular disease (CVD) risk. Lipoprotein characteristics including increased small dense low-density lipoprotein (LDL) particles are known independent risk factors for CVD. We hypothesized that reduced GH secretion in obesity would be associated with a more atherogenic lipid profile including increased small dense LDL particles. To evaluate this hypothesis, we studied 102 normal weight and obese men and women using standard GH stimulation testing to assess GH secretory capacity and performed comprehensive lipoprotein analyses including determination of lipoprotein particle size and subclass concentrations using proton NMR spectroscopy. Obese subjects were stratified into reduced or sufficient GH secretion based on the median peak-stimulated GH (≤6·25 μg/l). Obese subjects with reduced GH secretion (n = 35) demonstrated a smaller mean LDL and HDL particle size in comparison to normal weight subjects (n = 33) or obese subjects with sufficient GH (n = 34) by ANOVA (P < 0·0001). Univariate analyses demonstrated peak-stimulated GH was positively associated with LDL (r = 0·50; P < 0·0001) and HDL (r = 0·57; P < 0·0001), but not VLDL (P = 0·06) particle size. Multivariate regression analysis controlling for age, gender, race, ethnicity, tobacco, use of lipid-lowering medication, BMI and HOMA demonstrated peak-stimulated GH remained significantly associated with LDL particle size (β = 0·01; P = 0·01; R(2) = 0·42; P < 0·0001 for overall model) and HDL particle size (β = 0·008; P = 0·001; R(2) = 0·44; P < 0·0001 for overall model). These results suggest reduced peak-stimulated GH in obesity is independently associated with a more atherogenic lipoprotein profile defined in terms of particle size.Clinical Endocrinology 08/2011; 76(2):220-7. DOI:10.1111/j.1365-2265.2011.04195.x · 3.35 Impact Factor
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ABSTRACT: GH replacement lowers total cholesterol and low-density lipoprotein cholesterol (LDL-C) in GH-deficient adults, but effects on high-density lipoprotein (HDL) cholesterol (HDL-C) are variable. Both GH and glucocorticoids decrease cholesteryl ester transfer protein (CETP) activity, which is important in HDL metabolism. We determined the extent to which the changes in HDL-C in response to GH replacement are predicted by the -629C>A CETP promoter polymorphism, and questioned whether this association is modified by concomitant glucocorticoid treatment. A total of 91 GH-deficient adults (63 receiving glucocorticoids) were genotyped for the -629 CETP C>A polymorphism. Fasting serum lipids were measured before and after 1.2+/-0.4 years of GH treatment (Genotropin, Pfizer Inc., Stockholm, Sweden). In the whole group, total cholesterol and LDL-C decreased (P<0.05) after GH treatment, but the changes in HDL-C were not significant. In CC carriers receiving glucocorticoids (n=19), HDL-C rose by 0.15+/-0.25 mmol/l (P=0.02; P<0.03 from unchanged HDL-C in -629 AA+CA carriers on glucocorticoids and from CC homozygotes not receiving glucocorticoids). Multivariate regression analysis showed that individual changes in HDL-C were predicted by the CETP polymorphism (CC versus AA+CC, P=0.006) in glucocorticoid users, independently of baseline HDL-C and other variables including apolipoprotein E4 carrier status; an opposite association with the CETP polymorphism was found in patients not receiving glucocorticoids (P=0.053). We suggest a common CETP variant-glucocorticoid treatment interaction concerning the effect of GH replacement on HDL-C. This may explain some of the reported variation in the HDL-C response to GH.European Journal of Endocrinology 11/2009; 162(2). DOI:10.1530/EJE-09-0742 · 3.69 Impact Factor