Lawrence C.H. Tang

Stimulation of the zona-free hamster ova penetration efficiency by human spermatozoa after 17β-estradiol treatment

17 beta-Estradiol (E2) stimulated the zona-free hamster ova penetration by human spermatozoa from both fertile and subfertile men after 5 hours of incubation in vitro. For spermatozoa samples from fertile men, the mean penetration rates increased significantly (P less than 0.05), from 35.6% +/- 3.5% (control) to 60.1% +/- 5.8% (E2 = 50 ng/ ml) and 50.5% +/- 2.6% (E2 = 100 ng/ml), respectively. E2 also increased the mean penetration rates of spermatozoa samples from subfertile men significantly (P less than 0.05), from 10.2% +/- 1.8% (control) to 30.5% +/- 7.2% (E2 = 50 ng/ml) and 33.1% +/- 6.6% (E2 = 100 ng/ml), respectively. These findings indicate that E2 can affect the fertilizing ability of human spermatozoa in vitro.

Pregnancy in patients with mitral valve prolapse

The obstetrical performances and outcomes of 37 pregnancies in women with mitral valve prolapse between 1979 and 1982 are reviewed. Thirteen patients were diagnosed before pregnancy and 24 patients were detected at antenatal examinations. Three ended in cesarean sections for obstetrical complications and 34 in uneventful vaginal deliveries at term. No cardiac complications occurred in these patients. There was no maternal mortality. Thirty‐six babies were born without congenital abnormalities. One baby was hydropic due to haemoglobinopathy and died. Prophylactic antibiotics is recommended in selected cases. Early detection and treatment of cardiac arrhythmias is mandatory.

Seminal plasma transferrin and seminiferous tubular dysfunction

Seminal plasma transferrin levels were assayed in 158 random semen samples collected from normospermic, oligospermic, and azoospermic men, and their relationships with seminal characteristics, sperm fertilizing capacity as assessed by the zona-free hamster ova penetration assay, and serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were evaluated. The concentrations of seminal plasma transferrin in azoospermic, oligospermic and postvasectomy samples were significantly lower than those in normospermic samples. Seminal plasma transferrin concentrations were similar in azoospermia due to obstruction of the reproductive tract or damage to the germinal epithelium. No significant difference in seminal plasma transferrin concentrations was observed in the groups of subjects with normal and elevated FSH or normal and elevated LH. A positive correlation was observed between seminal plasma transferrin concentration and sperm density and between total semen transferrin content and the total number of sperm in the ejaculate. There were no significant correlations between seminal plasma transferrin concentration and sperm motility, percent normal sperm, sperm fertilizing capacity, and serum FSH or LH concentration. The results indicate that seminal plasma transferrin is not a useful marker for Sertoli cell or seminiferous tubular dysfunction. In addition, it is doubtful that measurement of seminal plasma transferrin will yield additional information regarding the fertility potential of semen samples.

Relationships of Seminal Plasma Prolactin with Spermatozoal Characteristics and Fertilizing Capacity in Vitro

Seminal plasma prolactin (PRL) levels were determined in 224 semen samples collected from fertile and suspected infertile men, and their relationships with spermatozoal characteristics and fertilizing capacity in vitro were evaluated. PRL concentrations were similar in normospermic and oligospermic samples, but were significantly lower in azoospermic samples. PRL concentrations were significantly higher in samples with high spermatozoal motility than in those with low spermatozoal motility. There were no significant differences in PRL concentrations between normal-morphology and abnormal-morphology samples, and between high-fertilizing capacity and low-fertilizing capacity samples. A low degree of positive correlation was observed between the PRL concentration and the spermatozoal motility. There were no significant correlations between the PRL levels, the other spermatozoal characteristics, and the spermatozoal fertilizing capacity in vitro. These findings indicate that the seminal plasma PRL levels are significantly depressed in azoospermic subjects and suggest that the seminal plasma PRL may play a role in the maintenance of spermatozoal motility. Whether there is a potential function of prolactin in semen on spermatozoal fertilizing capacity, however, cannot be inferred from the present study.

Effects of androgens on fertilizing capacity of human spermatozoa.

The potential functions of testosterone and 5 alpha-dihydrotestosterone, the androgens normally present in human seminal plasma, on human spermatozoal physiology were evaluated by studying the effects of these two steroid hormones on the in vitro fertilizing capacity of human spermatozoa. Spermatozoa collected from presumably fertile men were washed in BWW medium and incubated with different concentrations (0, 100, 250, 500, 1000 pg/ml) of testosterone or 5 alpha-dihydrotestosterone for 5 hr before insemination of the zona-free hamster ova. Penetration of the zona-free hamster ova was scored 6 hr later and the results were analyzed statistically. Both testosterone and 5 alpha-dihydrotestosterone, at the concentrations tested, significantly decreased the in vitro penetration of the denuded hamster ova in comparison to the controls (p less than 0.05). A dose-dependent response was also observed for the 5 alpha-dihydrotestosterone tested. These findings indicate that exogenous testosterone and 5 alpha-dihydrotestosterone can inhibit the fertilizing capacity of human spermatozoa in vitro, and suggest that the androgens normally present in human seminal plasma may serve, in part, to prevent premature spermatozoal capacitation before the spermatozoa reach the site of fertilization in vivo.

Effect of clomiphene citrate on human spermatozoal motility and fertilizing capacity in vitro

The effect of clomiphene citrate (CC) at various concentrations (0.005, 0.05, 0.5, 5, and 50 micrograms/ml) on the in vitro motility and fertilizing capacity of human spermatozoa was studied. Spermatozoa collected from 14 normal men were washed in modified Krebs-Ringer solution (Biggers, Whitten and Whittingham [BWW] medium) and incubated with CC for 5 hours, the period required for spermatozoal capacitation. The percent motilities of spermatozoa were recorded at 0 and 5 hours during incubation with CC. After incubation, the spermatozoa were washed with BWW medium to remove CC before insemination of the zona-free hamster ova. CC caused a significant dose-dependent decrease in the penetration of denuded hamster ova in comparison with the control (P less than 0.05). Significant depressive effect on spermatozoal motility was observed with CC at 0.05 micrograms/ml or higher concentrations (P less than 0.05). These results indicate that (1) CC decreases human spermatozoal fertilizing capacity in vitro and (2) the inhibitory effect on fertilizing capacity could be due to the sperm-immobilizing activity of CC.

Effect of reserpine on fertilizing capacity of human spermatozoa

The effect of reserpine at various concentrations (2 X 10(-6), 2 X 10(-7), 2 X 10(-8), 2 X 10(-9) and 2 X 10(-10) M) on the in vitro fertilizing capacity of human spermatozoa was studied. Spermatozoa collected from presumably fertile men were washed in BWW medium and incubated with different concentrations of reserpine for 5 hr before insemination of the zona-free hamster ova. The spermatozoal penetration of the zona-free hamster ova was scored 6 hr later and the results were analyzed statistically. Reserpine, at all the concentrations tested, caused a significant dose-dependent decrease in the penetration of the denuded hamster ova in comparison to the control (p less than 0.05). The percent motility of spermatozoa decreased as a function of time during the preincubation period to initiate spermatozoal capacitation but there were no significant differences in the values between the control and the reserpine - treated spermatozoa (p greater than 0.05). These findings indicate that reserpine can affect the fertilizing capacity of human spermatozoa in vitro and provide an additional evidence to suggest the prospective use of reserpine as a vaginal contraceptive.

Clomiphene citrate does not improve spermatozoal fertilizing capacity in idiopathic oligospermia

Clomiphene citrate (CC) was given to 24 men with idiopathic oligospermia at a daily dose of 25mg (10 subjects) or 50mg (14 subjects). Sperm concentration increased slightly after CC treatment in both groups. Sperm motility and morphology remained unchanged. Spermatozoal fertilizing capacity as assessed by the zona-free hamster ova penetration test showed no significant change throughout the treatment period. Two pregnancies occurred in the partners of the subjects treated with 50mg CC/day, but none occurred in the other group. We conclude that oral administration of CC does not improve fertilizing capacity of sperm as measured by the zona-free hamster ova penetration test in idiopathic oligospermia.

Immunoreactive LHRH-like factor in human seminal plasma.

Luteinizing hormone releasing hormone (LHRH)-like factor was detected in human seminal plasma by radioimmunoassay. The concentrations of immunoreactive LHRH in all semen samples tested (n = 46) ranged from 31 pg/ml to 71 pg/ml. Total content per ejaculate (pg) varied between 58 pg and 329 pg. There were no significant differences (p greater than 0.05) in the concentrations or total contents of immunoreactive LHRH-like factor between normospermic, oligospermic, and azoospermic semen samples.

Lack of Effect of Exogenous Prolactin on the Fertilizing Capacity of Human Spermatozoa in Vitro

The effect of exogenous prolactin (PRL) on the fertilizing capacity of human spermatozoa in vitro was evaluated by the zona-free hamster ova penetration assay. Bovine and ovine PRL, in both physiological and pharmacological concentrations, failed to increase the penetration after 5 hr of incubation in vitro. The percent motility of spermatozoa was not influenced by PRL during the incubation period. Exogenous PRL does not affect the fertilizing capacity of human spermatozoa in vitro. The role of prolactin, normally present in seminal plasma and female reproductive tract fluid, in the human spermatozoal capacitation process merits further investigation.