Pituitary-gonadal function in male patients with myotonic dystrophy- serum luteinizing hormone, follicle stimulating hormone and testosterone levels and histological dmaage of the testis.

Variations in serum levels of LH and FSH after administration of synthetic LH-RH, and basal levels of serum testosterone were studied in 9 male patients with myotonic dystrophy. The degree of testicular damage, as determined histologically on biopsy specimens, was also studied. Results were as follows: 1) it was observed that both the basal and stimulated (maximal) levels of serum LH and FSH were significantly higher than levels found in 9 sex- and age-matched normal controls. 2) The basal level of serum testosterone was consistently lower in the patient group. One patient, however, showed a low normal level, which represented a statistically significant reciprocal relation to both LH and FSH levels as expressed on a logarithmic scale. 3) There was a significant trend which indicated that the higher the serum LH, FSH levels, or the lower the basal levels of serum testosterone, the more extensive was the damage to the seminiferous tubules. From these findings it was concluded that hypogonadism in patients with myotonic dystrophy, is characterized by the development of lesions in the seminiferous tubules.