Increased serum FSH levels correlated with low and high sperm counts in male infertile patients.

Serum FSH, LH and testosterone were measured in 57 (42) normal men and in 80 male infertile patients. In the former, mean (x) FSH was found to be 2.5 ng/ml with a range (x +/- 2 SD) from 0.25 ng/ml to 5.3 ng/ml, mean LH was 2.2 ng/ml with a range from 0.5 ng/ml to 5.6 ng/ml, and mean testosterone was 540 ng/100 ml with a range from 190 mg/ml to 890 ng/100 ml. Immunoassayable FSH was found to be elevated in 17 out of 42 presumably infertile males with sperm counts below 20 million/ml, and in 5 out of 12 men with sperm counts above 120 million/ml. There was no correlation between testosterone and sperm number, motility, and seminal fructose content. The concurrence of depressed spermatogenesis and elevated FSH levels seems to be a relatively good indicator for the presence of organic disorders of the testis.