Alterations of neuroendocrine functions in spinal cord injury

A transverse myelopathy causes a marked dysfunction in the negative feedback of some of the hypothalamo-hypophyseal-target organ axes. Spinal cord injured (SCI) humans with lesions above T6 exhibit significantly lower serum LH and testosterone but not FSH. The parathyroid hormone-thyrocalcitonin regulation of bone metabolism is disturbed; the higher the lesion, the greater is the loss of mineral and matrix components of the bone. Further, the response to insulin induced hypoglycemia is blunted in SCI with high lesions, and their basal levels of norepinephrine, epinephrine, and cortisol are significantly lower than those of controls. Distension of the bladder or rectum, however, produces marked release of norepinephrine and concomitant increase in sympathetic activity. The results suggest impaired hypothalamo-hypophyseal-testicular, -adrenocortical, - adrenomedulary, -sympathetic axis dysfunction.