Serum testosterone and growth hormone/insulin-like growth factor-I in adults with spinal cord injury

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).(ABSTRACT TRUNCATED AT 250 WORDS)