The assessment of sperm velocity and prolactin in the infertile male

The first part of the study comprises the development of a method of measuring sperm velocity (p=/sec) by time-lapse photography (TLP). Recordings were performed in 50 infertile men and compared to 20 fertile men. TLP was found to be an accurate method of measuring sperm velocity with a low coefficient of variation. Its accuracy is limited at low sperm density levels (less than 5 million/ml). Sperm velocity is a separate parameter from percentage motility and sperm density. It is not dependent on serum hormonal levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), 17p oestradiol and dihydrotestosterone (DHT). A statistically significant difference in sperm velocity was found between the two groups studied and no fertile male had a sperm velocity of less than 30 µm/sec. The importance of sperm velocity as a new parameter in the investigation of male infertility is discussed. A statistically significant difference in the levels of serum 17p oestradiol was also noted between fertile and infertile men. The second part studies the role of serum prolactin in spermatogenesis using the same infertile (50) and fertile (20) patients. There was no statistical difference in either serum or seminal prolactin between the two grcups. In the infertile patients FSH levels were found to correlate with prolactin at both serum and seminal levels. Serum LH was also correlated with seminal prolactin. No such correlations were found in the fertile group. The 50 infertile patients were randomly separated into two groups and received Bromocriptine 2.5 mg b.d. or placebo on a double-blind parallel group basis. The patients were re-assessed after three and six months treatment. Bromocriptine is an effective prolactin-lowering agent at both set- and seminal level. Bromocriptine has a deleterious effect on sperm production and no apparent effect on androgen metabolism. Dihydrotestosterone (DHT) progressively rose in both placebo and Bromocriptine treated groups and it is suggested that this might explain the apparent beneficial effect on spermatogenesis by placebo noted in other series.