Human Chorionic Gonadotropin β-Subunit in Human Semen

Abstract

The level of human seminal chorionic gonadotropin β-subunit (hCGβ) was determined by radioimmunoassay (R1A). The mean hCGβ level in 34 normal men was 3.7 ±1.6 ng/ml, which was much higher than that in serum. The mean hCG/3 level for 20 patients with mild oligozoospermia (20–39 × 10⁶ sperm/ml) was 2.5 ± 0.8 ng/ml, that for 34 patients with severe oligozoospermia (1–19 × 10⁶ sperm/ ml) was 1.7 ± 0.5 ng/ml, and that for 21 azoospermia was 1.5 ± 0.6 ng/ml. Thus, the decrease of sperm count was correlated with the decrease of hCGβ. In 17 cases to which testicular biopsy was applied together with sperm counting, the seminal hCGβ level was found to positively correlate with the germinal cell index (die ratio germinal cell count/Sertoli cell count) and with the testicular volume. The level of seminal hCGβ was also found to correlate negatively with the levels of seminal LH and FSH and positively with the Wei of seminal testosterone. These findings suggest that the production of seminal hCGβ is a process of spermatogenesis and closely related to spermatogenesis. The level of hCGβ in serum was too low to detect, and no relation to that in seminal plasma could be investigated. However, in 6 cases with testicular tumor, the hCGβ level in serum was high, whereas that in seminal plasma was rather low probably because of unilateral secretion. Enhanced production of hCGβ by tumor tissues and the detraction of the blood-testis barrier by proliferation of tumor cells seemed to be one of the causes of this high hCG0 level in serum. The hCGβ levels in 13 vasectomized seminal plasma and the prostatic fluid samples collected from 3 normal men were 1.5 ng/ml, which was similar to those in azoospermic patients. These findings suggest that the seminal hCGβ level consists of the hCGβ secreted by the testis and about 1.5 ng/ml of hCGβ from the prostate. Based on these results, seminal hCGβ is thought to be secreted by the prostate and the process of spermatogenesis and the value of seminal hCGβ may serve as an effective index for the testicular function.

Key Words:

• hCGβ
• Seminal plasma
• Testicular function
• Male infertility