EFFECT OF SHORT-TERM RECOMBINANT GROWTH-HORMONE ADMINISTRATION ON PLASMA-LIPOPROTEINS IN ELDERLY ADULTS

To characterize the effects of recombinant human growth hormone (rhGH) on plasma lipids and lipoproteins, rhGH was administered daily at a d ose of 40 mu g.kg(-1) (Genentech) for 14 days in 7 healthy elderly mal e (67.4 +/- 1.9 years, 75.8 +/- 2.6 kg) adults. Six other healthy male s (63.9 +/- 0.7 years, 77.8 +/- 3.8 kg) served as concurrent controls. Total plasma cholesterol (TC), triglycerides (TG), very-low-density l ipoprotein-cholesterol, low-density lipoprotein-cholesterol, high-dens ity lipoprotein-cholesterol, very-low-density lipoprotein-TG (VLDL-TG) and apolipoprotein AI and apolipoprotein B were determined after an o vernight fast before and after the 14-day period of rhGH administratio n. Subcutaneous rhGH administration was physiologically effective, as shown by a threefold increase in insulin-like growth factor-I (from 11 0.8 +/- 8.2 to 355.5 +/- 41.6 ng.ml(-1); p < 0.05). Plasma fasting ins ulin also increased from 38.0 +/- 6.5 to 129.9 +/- 43.8 mu mol.l(-1) ( p < 0.05) at the end of the 14 days of rhGH treatment. With respect to plasma lipid/lipoprotein changes, rhGH administration increased plasm a TG levels (from 1.5 +/- 0.3 to 2.2 +/- 0.4 mmol l(-1); p < 0.05) and VLDL-TG (from 1.1 +/- 0.3 to 1.8 +/- 0.4 mmol.l(-1); p < 0.05), but d id not change TC (from 5.0 +/- 0.4 to 5.2 +/- 0.3 mmol.l(-1)) or any o ther lipid/lipoprotein variables measured. No significant lipid change s were noted in the control group over the 14-day period. These data s uggest that short-term rhGH treatment significantly alters plasma vari ables of TG profile, perhaps by altering metabolic parameters (i.e. sy nthesis and/or clearance rates) of VLDL metabolism.