The One Year Effects of Growth Hormone Replacement on the Body Composition in the Normal Adults

Kim, Eui Hyun; Chon, Suk; Koh, Kwan Pyo; Oh, Seong Joon; Woo, Jeong Taek; Kim, Sung Woon; Kim, Jin Woo; Kim, Young Seol

Abstract

BACKGROUND: The secretion of growth hormone [GH] declines by 14.4% every decade, leading to the suggestion that the elderly are functionally GH deficient, which may increase adipose tissue and decrease the bone mass and density, as well as other negative changes in body composition. Recently, many studies have shown that GH replacement therapy may restore the changes that occur in the body composition with aging. AIM: The GH and insulin like growth factor-I[IGF-I] profiles were identified during GH replacement therapy in the elderly and compared with those of GH deficient[GHD] patients. The metabolic effects of GH replacement on the body composition of the elderly was also investigated, especially the body fat, muscle and bone parameters. Subjects and METHODS: 98 healthy normal out-patients and 13 GHD patients, who had peak GH concentrations less than 5 ng/mL after an insulin tolerance test [ITT] or growth hormone releasing hormone [GHRH] stimulation test, were the subjects of this study. All were receiving appropriate thyroid, adrenal and gonadal hormone replacements. The dose of recombinant human GH [rhGH] was 0.02~0.04 mg [0.06~0.12 IU]/kg of body weight.per week, given nightly by a subcutaneous injection, six times a week, over a 52 week period. The GH was measures after the ITT and GHRH stimulation tests, and the IGF-1, lipid parameters [total cholesterol, triglyceride, HDL-, and LDL cholesterol], visceral adipose tissue [VAT], subcutaneous adipose tissue [SAT], VAT/SAT ratio, quadriceps muscle area, total body fat, total bone mineral density [BMD], alkaline phosphatase [ALP], osteocalcin and urine deoxypyridinoline [DYP], as well as anthropometry, were also assessed.
RESULTS
All the anthropometry features between the normal and GHD subjects were very similar. The hormonal profiles were checked; the GH peaks of the ITT and GHRH stimulation tests were significantly higher in the normal compared to the GHD patients, but the GHRH test showed lower GH peaks in than those of the ITT test in the normal subjects. The IGF-I levels after GH replacement were constantly maintained in the normal and GHD groups after 3 week and until the 52nd week. According to the lipid profiles, the GHD group showed significantly decreased total cholesterol and LDL-cholesterol after 12 weeks of GH replacement. The normal male group revealed constantly increased triglyceride levels during the entire 52 weeks of GH replacement, but thr other lipid parameters remained completely unchanged. The normal female group showed no change in any of their lipid parameters. Although the amounts of VAT at the baseline were the same in all groups, only the normal males showed effective visceral fat removal, with significantly reduced VAT after 52 weeks of GH treatment. In the normal female and GHD groups the bone mineral density had a V shaped curve after GH replacement, and the ALP and osteocalcin levels were significantly increased after 26 weeks of GH therapy in the GHD group.
CONCLUSION
The body compositions in the normal male, female and GHD groups were similar before the GH replacement therapy, and the serum IGF-I levels were well maintained in all these groups during GH replacement. Although the majority of aging symptoms were improved, the body compositions tended to return to their original stati in the normal groups. GH replacement is recommended in the elderly for better health and well-being

The One Year Effects of Growth Hormone Replacement on the Body Composition in the Normal Adults

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