Abstract. Six men requesting male contraception received a daily oral dose of 20 mg medroxyprogesterone acetate (MPA) in combination with 50 or 100 mg percutaneous testosterone for 1 year. From the third month the sperm concentration was < 106/ml for all the men at one time or another during treatment, and usually < 5 × 106/ml, with an average reduction of 95% with respect to pre-treatment values. The sperm count returned to previous values 3–6 months after cessation of the treatment. While FSH and LH secretion was inhibited throughout the treatment period, plasma testosterone levels were not reduced. Oestradiol levels were unaffected while dihydrotestosterone was elevated. The secretory activity of the prostate and seminal vesicles was not appreciably affected; seminal carnitine concentration was reduced during the treatment with a subsequent return to pretreatment values. No pregnancies occurred during treatment. There was no impairment of libido in the subjects, nor any incidence of gynaecomastia, or increase in average body weight. The only observed metabolic side-effect was a moderate increase in glycaemia. A synergistic action of MPA and testosterone is proposed to explain the inhibition of gonadotrophin secretion.

The efficiency of cervical mucus in filtering out single, multiple and associated abnormalities of human spermatozoa was determined. Twenty semen samples which gave a normal in vitro cervical mucus penetration test (CMPT) were analysed before and after migration using a detailed classification system (13 categories). The % of normal forms was significantly increased in cervical mucus (59.5 vs 33.2%), whereas the % of sperm with single, multiple or associated abnormalities of the midpiece or of the flagellum were found to decrease significantly in cervical mucus. Sperm with single or multiple abnormalities confined to the head migrated similarly to normal forms. The decrease in amorphous and elongated tapering sperm was explained by their more frequent association with other defects of the midpiece and/or of the flagellum.

Semen samples from 120 infertile men with suspected autoimmunity to sperm were investigated by a direct immunobead test (IBT). Fifty-three (44%) of them had 10% or more motile sperm coated with anti-IgG and/or anti-IgA immunobeads. Both classes of immunoglobulins were found to be present in 88.7% of the antibody positive ejaculates. These sperm-bound Igs were associated with sperm autoagglutination in 80% of the ejaculates and with decreased sperm penetration into cervical mucus in 97.6% of the cases. The close correlation found between the IBT results and the occurrence of antisperm antibodies in serum and in seminal plasma suggests that sperm-bound Ig's are sperm-specific antibodies. It is concluded that the direct IBT is not only a reliable screening test for sperm antibodies but is also a relevant test to determine whether these antibodies exert an influence on male fertility.

Data about the levels of free L-carnitine, an epididymal marker in human semen, are contradictory and unclear, particularly in their relationship to fertility. This can perhaps be explained by the absence of any studies of seminal L-carnitine in a large group of fertile men, and by the lack of consideration of factors influencing its secretion. In this study, free L-carnitine was determined using a spectrophotometric method in deproteinized semen samples from fertile (n = 162) and infertile men without azoospermia (n = 303). Our results can be summarized as follows: Infertile men were found to have significantly lower (P less than 0.001) seminal carnitine levels (755 +/- SD 499 nmoles) compared with fertile men (1010 +/- 570). Percentiles have been calculated for fertile men, and 'normal' values proposed (10th percentile = 390 and 90th percentile = 1830 nmoles). Distribution of the levels of L-carnitine were asymmetric in fertile as well as in infertile men (median: 922 nmoles vs 645). In both groups, a significant increase in carnitine levels was observed with increasing length of abstinence, and a decrease in the ratio of carnitine/days of abstinence. Methodological, physiological and pathological factors which may explain these results are discussed.

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