The concentrations of magnesium and zinc in the seminal fluid of 41 patients with symptoms of non-acute prostatitis and of 11 healthy age-matched males were determined by atomic absorption spectrophotometry. Possible sources of error in the determination of these metals in seminal fluid are discussed. The mean concentration of magnesium in the patients was 56.6 mug/ml (range 19-190) and in the controls 64.5 mug/ml (range 36-165). The corresponding figures for zinc were 79.2 mug/ml (range 13-283) and 67.5 mug/mg (range 34-116). Both in the patients and in the controls there was a significant correlation between the concentration of magnesium and that of zinc. No significant difference was found between the patients and the controls regarding the concentration of magnesium or zinc. From none of the patients could gonococci be cultured. However, in 6 of them, immunofluorescent studies revealed gonococci. The concentration of zinc (48.3 mug/ml) in seminal fluid from these 6 patients was significantly lower than in the remaining 35. Neither in the patients, nor in the controls, was any correlation found between the concentration of magnesium or zinc and that of fructose in seminal fluid. A significant correlation was found between the concentrations of these metals and the antibacterial activity (determined as the inhibitory effect on the growth of Staphylococcus albus) of the seminal fluid from the patients. A negative correlation was found between the concentration of zinc and an increase in the number of white blood cells in expressed prostatic fluid. No correlation was found between magnesium or zinc and the number of spermatozoa or the percentage of abnormal spermatozoa. The findings in the present study suggest that the secretion of magnesium and zinc is decreased in prostatitis. Because of the wide range of variation of magnesium and zinc in seminal fluid of healthy males, determination of these metals is of limited value in the diagnoses of prostatitis in a given case.
