Horm Metab Res 1995; 27(6): 287-292
DOI: 10.1055/s-2007-979961
Originals Clinical

© Georg Thieme Verlag Stuttgart · New York

Serum Testosterone and Growth Hormone Insulin-Like Growth Factor-I in Adults with Spinal Cord Injury

P. D. Tsitouras, Y.-G. Zhong, Ann M. Spungen, W. A. Bauman
  • The Spinal Cord Damage Research Center and Departments of Medicine, Geriatrics and Rehabilitation Medicine, Mount Sinai Medical Center, New York, Spinal Cord Injury, Geriatrics and Medical Services, Veterans Affairs Medical Center, Bronx, U.S.A.
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Publication Date:
23 April 2007 (online)


Aging is associated with relative growth hormone and/or testosterone (T) hormone deficiency, and those with SCI may have a premature deficiency of these two hormones. The effects of SCI, duration of injury (DOI), and advancing age with that of human growth hormone (hGH) and insulin-like growth factor I (IGF-I), as well as potential associations between them, were studied. Data were obtained from 20 male subjects with SCI and 16 gender- and age-matched controls. Serum total and free T were lower in subjects with SCI compared with controls (mean ± SEM, 3.12 ± 0.29 versus 4.68 ± 0.28 ng/ml, p < 0.001 and 1.89 ± 0.18 versus 2.46 ± 0.22 ng/ml, p < 0.05, respectively). Nine of the 20 subjects with SCI, but none of the controls, had abnormally low serum total T. Arginine-stimulated values for hGH were lower in the group with SCI compared with controls (198 ± 18 versus 267 ± 27 ng/ml, p < 0.05). Serum luteinizing hormone and follicular stimulating hormone, as well as body mass index, were not significantly different between the groups. Serum total and free T were correlated with advancing age in controls (r = 0.62, p < 0.01 and r = 0.51, < 0.05, respectively) but not in SCI (r = 0.19, p > 0.43 and r = 0.39, p = 0.09). However, serum total and free T declined with increasing DOI in SCI (r = 0.56, p < 0.01 and r = 0.44, p = 0.05, respectively). Serum IGF-I appeared to decline with advancing age in SCI (r = 0.51, p 0.02), but the decrease in serum IGF-I with age was stronger in controls (r = 0.77, p = 0.0005). In the total group, age had no significant effect on hGH, but age did have a significant effect on serum total T (r = 0.40, p = 0.02). The multiple regression of peak hGH response given age on serum total T was significant (R = 0.51, p < 0.01); peak hGH had an independent effect over and above age on serum total T (partial r = 0.38, p < 0.05). A nonlinear relationship was found between serum free T and IGF-I (r = 0.61, p = 0.02), where serum free T appears to plateau when serum IGF-I is equal to or greater than 250 ng/ml. In controls, a nonsignificant relationship could be demonstrated between serum total T and IGF-I (r = 0.48, p = 0.06). Our findings suggest that SCI is associated with impaired secretion of both T and hGH, which is not the result of advancing age per se. DOI appears to have an adverse effect on serum T, a finding compatible with the hypothesis that those with SCI have a condition which predisposes to age-related changes.