Suppression of the Hypothalamus-Pituitary Somatotrope Axis in Men with Spinal Cord Injuries

　　Thirty-two men with spinal cord injury(SCI) were studied for evaluation of the hypothalamus-pituitary somatotrope axis, using growth hormone-(GH)-releasing hormone(GHRH) and insulin-induced hypoglycemia. Twenty- six age-matched normal male volunteers served as controls. Six SCI subjects (18.7％) had elevated basal follicle- stimulating hormone (FSH) levels, eight (25.0％) had hyperprolactinemia, and 11(34.4％) had reduced serum insulin -like growth factor-1 (IGF-1) levels. Twenty SCI subjects(62 .5％) had reduced and/or delayed GH responses to GHRH, and eight (25.8％) had reduced GH response to insulin-induced hypoglycemia. Seven of eight hyperprolactinemic SCI subjects showed reduced GH response to GHRH and /or insulin-induced hypoglycemia. These findings are consistent with the notion that SCI subjects have a reduced central dopaminergic tone.