EFFECTS OF GH AND SEX STEROID REPLACEMENT IN HEALTHY WOMEN AND MEN OVER 65 YEARS OF AGE





S.M. Harman, M.R. Blackman

Kronos Research Institute
4455 East Camelback Road - Ste. B-135
Phoenix, AZ 85254




Aging is associated with decreased circulating GH, IGF-I, and sex steroids, reduced lean body mass (LBM), strength, and endurance, and increased total and abdominal body fat (BF). Loss of muscle mass may contribute to weakness and frailty, and increased fat to glucose intolerance, dyslipidemia, and cardiovascular risk. In a double-blind, placebo controlled, randomized study, we assessed the effects of 6 mo of administration of GH, sex steroid(s) (EstradermŽ+ProveraŽ = HRT in women; testosterone enanthate = TE in men), or GH+sex steroid on LBM and % BF by DEXA; muscle strength by 1-repetition maximum testing; and VO2max (ml/Kg BW) by graded treadmill exercise tests in healthy women (n=52) and men (n=71), ages 65-88 (mean 72) y, with baseline reductions in serum IGF-I and gonadal steroid levels. In men, GH increased LBM by 5.7% (p<0.0001) vs. placebo; TE, by 3.1% (p<0.05); and GH+TE, by 8.3% (p<0.0001). In women, GH increased LBM by 5.8% (p<0.0001); HRT, by 3.0% (p<0.01); and GH+HRT, by 6.8% (p<0.0001). In men, GH+TE increased total body strength by 7.5% (p<0.05), which was due to increases in several upper body strength measures. There was no significant hormone effect on strength in women. VO2max increased in men treated with GH+TE (p<0.001), and in women treated with GH (p<0.01) or GH+HRT (p<0.05). VO2max changes were directly related to increases in LBM (r=0.48; p<0.0001). In men, GH decreased % BF by 13% (p<0.0001); TE, by 5.8% (p<0.05); and GH+TE, by 21% (p<0.0001). In women, GH decreased % BF by 8.0% (p<0.005); HRT, by 3.2% (NS); and GH+HRT, by 10.0% (p<0.0001). In men GH+TE effects exceeded those of GH or TE alone on LBM (p<0.05; p<0.0001) and on %BF (p<.005; p<0.0001). Our data show that GH and sex steroids given to healthy elderly individuals produce potentially beneficial changes in body composition, and that, in men, TE adds to the effects of GH on LBM, strength, cardiac endurance and body fat. Longer-term studies are warranted to assess the benefit/risk ratio of more physiological manipulations of the GH axis, with or without sex steroid replacement, before such hormone supplementation can be justified in healthy or frail elderly populations




Key words: Growth hormone, strength, lean body mass, body fat mass, metabolism







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