Background: The objective of the study was to investigate the hypothalamo-pituitary-testicular axis and sperm structure at the transmission electron microscope (TEM) level in men affected by insulin-dependent diabetes.
Methods: Twenty-two diabetic men and 24 controls were recruited. GnRH (100 micro g) was administered and FSH- and LH-induced secretion was evaluated. Semen samples were collected and sperm concentration and motility were determined using a Makler chamber. Ejaculated sperm were fixed and observed with a TEM.
Results: The response of gonadotrophins to GnRH was significantly lower in diabetics than in control men. Sperm motility was also significantly lower. At the electron microscope level, sperm from diabetics exhibited a higher percentage of immaturity- and apoptosis-related defects than sperm from controls.
Conclusions: The reduced response of gonadotrophins to GnRH in diabetic men may indicate a decreased acute releasable pool of pituitary gonadotrophins. The results of TEM examination showed that sperm from men with diabetes presented severe structural defects in comparison with sperm from controls. It is possible that the reproductive impairment recognized in men with diabetes could be the result of interference by the disease on the hypothalamo-pituitary-testicular axis at multiple levels, as indicated by the reduced gonadotrophin response to appropriate stimuli and by the abnormal ultrastructure of ejaculated sperm. The defective spermatogenesis may be the consequence of a direct testicular effect of the disease.