purpose To evaluate the hypothalamic–pituitary–testis (HPT) axis, endocrine profiles and semen quality in men with spinal cord injury (SCI).
materials and methods Fifty-five men with SCI were studied. Serum levels of FSH, LH, testosterone, oestradiol and prolactin (PRL) were determined; the LH-releasing hormone (LHRH) stimulation test and a semen analysis were performed, and testicular volumes were measured. Thirty-six age-matched healthy male volunteers and 34 noninjured infertile men served as controls.
results Eight SCI subjects had low basal LH, four had low basal FSH, and 16 had decreased basal serum levels of LH and FSH. Of subjects with lower serum levels of gonadotrophins (LH and/or FSH), nine had low serum testosterone and seven had hyperprolactinaemia. Serum levels of oestradiol were similar for all groups. There were increased LH and FSH responses to LHRH in SCI subjects compared to normal controls, but this difference was only statistically significant in SCI subjects with lower than normal serum levels of LH and/or FSH. There was no significant difference in testis volume between SCI subjects and controls. The mean semen volume in SCI subjects was lower than from controls, but the difference was not statistically significant. Sperm motility and percent normal sperm morphology were lower in SCI compared to normal controls but not to infertile control subjects. In total, 51% and 86% of SCI subjects had at least one hormonal or axis abnormality, respectively.
conclusion We conclude that hypogonadotropism in SCI subjects is likely to be secondary to altered neural or hormonal pathways between the hypothalamus and the pituitary gland, and that these endocrine abnormalities may be the mechanisms contributing to impairment of semen quality.