No abstract

The fertility of male workers exposed to mercury vapor or to manganese dust was assessed with the use of the questionnaire developed by Levine et al [1980]. In the mercury group (concentration of mercury in urine ranging from 5.1 to 272.1 micrograms/g creatinine), no statistically significant difference was found between the observed number of children and that expected on the basis of the reproductive experience of a well-matched control group. On the contrary, by comparison with their corresponding controls, the manganese-exposed workers exhibited a statistically significant deficit in the number of children during their period of exposure to the metal. The airborne concentration of manganese dusts at the different workplaces ranged from 0.07 to 8.61 mg/m3 with a geometric mean of 0.94 mg/m3.

Large amounts of an immunoreactive relaxin-like peptide were demonstrated in human seminal plasma. The concentrations of this peptide were determined in seven healthy volunteers, and in twenty-eight non-selected male patients seeking advice for sterility. A wide range of immunoreactive relaxin concentrations was observed, varying between 1,240 pg and 73,000 pg of relaxin porcine equivalents per ml of seminal plasma. Given the very special assay medium of seminal plasma, particular attention was paid to the validity of the radioimmunoassay system when applied to this medium.

The effect of chronic hyperestrogenism on gonadal function was studied in three men who had estrogen-secreting Leydig cell tumors before unilateral orchidectomy and for 11-43 months after surgery. All three men had low plasma gonadotropin and testosterone levels and increased estradiol levels. Impairment of testicular steroidogenesis was also suggested by increased progesterone to 17-hydroxyprogesterone and 17-hydroxyprogesterone to androstenedione ratios in both spermatic venous plasma and the medium of Leydig tumor cells from one patient incubated in vitro. Before surgery, spermatogenesis was abnormal in two men. Testicular endocrine function and spermatogenesis did not return to normal after surgery. During the follow-up period, plasma gonadotropin levels were high in all three men, and testosterone was low normal. Estradiol levels decreased to normal immediately after surgery and then returned to the upper normal limit. The response to hCG stimulation in one man was subnormal. We conclude that chronic hyperestrogenism produced hypothalamo-pituitary inhibition as well as direct steroidogenic blockade at the testicular level. Long term impairment of both endocrine and exocrine testicular functions may be secondary to slowly reversible (or irreversible) estrogen-induced damage to tubular and Leydig cells.