Differences in blood and semen oxidative status in fertile and infertile men,and their relationship with sperm quality

Oxidative stress plays a fundamental role in the aetiology of male infertility by negatively affecting sperm quality and function. Assessment of blood and seminal plasma oxidative profiles might be a valuable tool to improve evaluation of sperm reproductive capacity and functional competence. This study examined the lipid-soluble antioxidant profile and levels of lipid peroxidation both in blood and seminal plasma samples of infertile and fertile males, in relation to semen parameters. Total antioxidant capacity (TAC) and vitamin E concentrations were significantly (P < 0.05) lower in seminal plasma of infertile men compared with fertile subjects; concurrently, a significant accumulation of malondialdehyde was found in infertile patients (P = 0.032 compared with controls), which was negatively correlated with sperm motility and morphology. In blood samples, infertile men presented lower concentrations of TAC, carotenoids and vitamin E than fertile subjects; TAC and carotenoids were positively correlated with sperm motility, morphology and concentration. Finally, blood TAC and vitamin E concentrations were positively correlated with the corresponding seminal values, confirming the close relationship between blood and semen antioxidants. All these results indicated the possibility of using not only seminal antioxidants but also blood antioxidants as biochemical markers to support sperm quality evaluation.Oxidative stress induced by reactive oxygen species (ROS) has been widely recognized as one of the major causes of male infertility; indeed, excessive ROS production can negatively impact sperm quality and function. The assessment of blood and seminal plasma oxidative profiles has been suggested as a valuable tool to improve the evaluation of sperm reproductive capacity and functional competence in infertile men. With this in mind, in the present study we examined the lipid soluble antioxidant profile (carotenoids and vitamins A and E) and the levels of lipid peroxidation (malondialdehyde; MDA) both in blood and seminal plasma samples of infertile and fertile males, in correlation with semen parameters namely motility, morphology and concentration. As a result, we obtained evidence that the total antioxidant capacity (TAC) and the concentrations of vitamin E of seminal plasma samples were significantly lower in infertile men than in fertile subjects; at the same time, a significant accumulation of MDA was found in infertile patients. MDA, in turn, negatively correlated with sperm motility and morphology, thus confirming that oxidative damage to lipids impairs sperm quality. In blood samples, infertile men presented lower TAC and lower concentrations of carotenoids and vitamin E than fertile subjects; interestingly, TAC and carotenoid concentrations were positively correlated with sperm motility, morphology, and concentration, confirming the close relationship between blood antioxidants and sperm quality. In conclusion, all these results suggested that the examination of blood and semen oxidative profiles might furnish useful information on sperm quality and function in infertile men.     

Levels of carnitine acetyltransferase in fertile and oligospermic infertile semen

Activities of carnitine acetyltransferase (CAT) were determined in fertile (greater than 40 X 10(6) sperm/ml) and oligospermic infertile semen (less than 15 X 10(6) sperm/ml). CAT specific activities (unit/10(6) sperm) appear to be similar in both kinds of semen i.e., 0.020 +/- 0.002 and 0.013 +/- 0.001 for fertile and oligospermic infertile sperm, respectively. When CAT activities were corrected as unit/mg protein and unit/mg DNA, the values in the fertile sperm were 0.130 +/- 0.010 and 8.97 +/- 0.50, respectively, while in the infertile sperm the values were 0.016 +/- 0.002 and 2.72 +/- 0.14. The lower value in the oligospermic infertile sperm is due to the much higher amount of these macromolecules in infertile sperm. On the other hand, CAT activities and the amount of protein appear to be similar in both fertile and oligospermic seminal plasma. Our results, therefore, suggest that the lower level of CAT in infertile semen is due to its lower sperm density.     

Seminal fluid androgen levels in infertile patients

Seminal fluid concentrations of testosterone (T), dihydrotestosterone (DHT), androstenedione (A), and 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol) were measured in 34 male patients of infertile couples. Patients were subdivided into oligospermic (less than 20 X 10(6)/mL) and asthenospermic (typical motility less than 20%; total motility less than 40%) groups. Steroids were measured by specific radioimmunoassay after ether extraction and celite column chromatography. 3 alpha-Diol was present in seminal fluid, and its concentration was significantly correlated with DHT (r = .49, P less than .05). In oligospermic patients, seminal levels of T (78 +/- 29 pg/mL, mean +/- SD) and DHT (323 +/- 132 pg/mL) were significantly reduced in comparison with normospermic men (T, 119 +/- 56, P less than .05; DHT, 557 +/- 255, P less than .01), while A and 3 alpha-diol concentrations were similar in the two groups. Seminal T and DHT levels were also reduced in asthenospermic specimens, which showed increased 3 alpha-diol concentrations (75 +/- 44 pg/mL) with respect to normokinetic samples (45 +/- 20, P less than .05). Finally, a positive linear relationship was observed between DHT and both sperm density (P less than .01) and total motility (P less than .01). These data demonstrate the existence of a significant amount of 3 alpha-diol in seminal plasma and suggest DHT as the androgen most closely related to sperm quality.     

Cytotoxic sperm antibodies inhibit sperm penetration of zona-free hamster eggs

Zona-free hamster egg sperm penetration assay was used to study the effects of cytotoxic sperm antibodies on egg penetration by the sperm of fertile and infertile men. Twenty-nine fertile and 9 infertile men did not have significant cytotoxic sperm antibodies in their serum and seminal plasma; 7 infertile men were positive for these antibodies in serum and seminal plasma. Two others were positive in sera, and 14 were positive in seminal plasma. Sperm from 18 of 23 (78%) infertile men with sperm antibodies had poor egg penetration (less than or equal to 20%) compared with only 6 of 38 (16%) nonautoimmune men (P less than 0.0001). Sperm from nonautoimmune fertile men were coated with seminal plasma and serum of autoimmune men and serum of isoimmune women, resulting in a significant decrease in hamster egg penetration. Sixteen of 21 (76%) seminal plasma samples with cytotoxic sperm antibodies reduced the control sperm penetration of hamster eggs by greater than or equal to 50%. Coating of sperm from fertile men with serum and seminal plasma samples from non-sperm-immune fertile and infertile subjects did not alter their penetration of hamster eggs. Coating of sperm from autoimmune men with cytotoxic antibody-positive autologous seminal plasma samples resulted in a significant decrease of egg penetration. The inhibitory effect of antibody-positive seminal plasma samples on egg penetration by control sperm was abrogated when the samples were preabsorbed with sperm. It is concluded that cytotoxic sperm antibodies, especially those in seminal plasma, inhibit hamster egg penetration by autologous and control sperm. This may explain in part the incidence of infertility associated with sperm antibodies.     

抗SPIM自身抗体的ELISA测定与临床应用

用ELISA 法定量检测生育、不育男性血清、精浆抗SPIM 自身抗体(SPIM-Ab)。结果表明:不育组和妻子流产组患者血清、精浆SPIM-Ab 含量均显著高于生育组(P<0.01),两组血清、精浆的SPIM-Ab 阳性率与生育组之间有显著性差异(P<0.01);精浆SPIM-Ab 含量高于5.0U/ml 时,精于密度、精子活率及精浆SPIM 活性均明显降低;SPIM-Ab 与血清、精浆抗精子抗体(AsAb)无明显关系。提示:SPIM-Ab 水平增加可能抑制SPIM 活性、与SPIM一起参与局部免疫反应,并减少精子密度和活率。     

Thymosin alpha 1 levels in human seminal plasma and follicular fluid: implication in germ cell function

High levels of thymosin alpha 1 (T alpha 1) were detected in human seminal plasma and follicular fluid. In the seminal plasma of 19 males studies, T alpha 1 levels varied from 614 to 2,604 pg/mL (mean +/- SD, 1,682.4 +/- 453.9 pg/mL). There was a correlation between the T alpha 1 levels and the total number of sperm in the ejaculate (r = .18) and seminal volume (r = .26). The infertile males, who had low levels of T alpha 1 also demonstrated fewer sperm, reduced motility, and lower semen volume. In follicular fluid collected from 24 follicles of 10 infertile females, T alpha 1 levels varied from 1,019 to 6,384 pg/mL (mean +/- SD, 3,572.8 +/- 1,599.7 pg/mL), which were higher when compared with the corresponding serum levels (mean +/- SD, 1,666.9 +/- 1,378.9 pg/mL). T alpha 1 levels present in follicular fluids which had "immature" oocytes were lower when compared with follicular fluids which had "intermediate" or "mature" oocytes. The immunoreactive T alpha 1 present in seminal plasma of males and in the follicular fluids of females may be involved in some aspect of germ cell maturation and function. The measurement of T alpha 1 levels may be useful in the diagnosis and treatment of male and female infertility, and also as a novel marker for the assessment of maturity of oocytes required for in vitro fertilization-embryo transfer.     

Oral immunization with sperm antigens: possible therapy for sperm antibodies?

Young adult male CD-1 mice were given intraperitoneal injections (IP) of saline (controls) and pooled sperm or seminal plasma of two autoimmune infertile men and two nonautoimmune fertile men (n = 40 per treatment). Other mice received only an oral challenge with the same antigens (oral controls; n = 20 per treatment). Three weeks after the booster challenge (day 36), 20 mice in each group were orally immunized with the antigens, whereas the other 20 were not (IP controls). Cytotoxic antibody titers (immunoglobulin M) to human sperm were significantly higher in mice IP immunized with sperm or seminal plasma from autoimmune infertile men or orally immunized with autoimmune men's sperm, in contrast to the controls. Oral challenge with sperm or seminal plasma of autoimmune infertile men after the IP immunization with the same resulted in significantly decreased cytotoxic sperm antibody titers (P less than 0.001 versus oral or IP controls in sperm immunization; P less than 0.001 versus IP controls in seminal plasma immunization). Fertility was unaffected by any mode of immunization. It is concluded that, in mice, sperm and seminal plasma antigens from autoimmune infertile men are more immunogenic than those from nonautoimmune fertile men, and oral challenge with the former after an IP establishment of cytotoxic sperm immunity desensitizes the immune mice. These findings may have practical implications in the diagnosis and immunotherapy of infertile men with cytotoxic sperm antibodies.     

人精浆与血清中生殖激素及免疫球蛋白的相关性研究

对152例生育与不育男性,分组观察精浆和血清中五种生殖激素(ICSH、FSH、PRL、T、E_2)及三种免疫球蛋白(IgG、IgA、IgM)的变化,分析它们之间的相关性以及与精液质量的关系。结果表明:1.生殖激素在精浆与血清中含量变化不一致。精浆中ICSH与PRL呈正相关,精浆ICSH、PRL与精于活力、密度间亦呈正相关关系。2.精浆IgG与血清、精浆T呈负相关,不育者精浆IgG与精子活力亦为负相关关系。     

溶脲脲原体感染不育者精浆α－葡萄糖苷酶活性及果糖含量的分析

本文比较了溶脲脲原体感染的不育男性与正常生育男性精浆中α－１，４－葡萄糖苷酶活性及果糖含量。结果表明，溶脲脲原体感染的不育肾性精浆中α－１，４－葡萄糖苷酶活性明显低于正常生育男性（分别为：Ｘ±ＳＤ＝２７．９９±２０．３１ｍＩＵ／ｍｌ和Ｘ±ＳＤ＝４１．８６±２１．８６ｍＩＵ／ＭＬ，ｐ＜０．０５）；溶脲脲原体感染的不育男性精浆中果糖含量（Ｘ±ＳＤ＝２３３．９６±８９．２１ｍｇ／ｄｌ）稍高于正常生育男性（Ｘ±ＳＤ＝１７９．８１±１０６．４５ｍｇ／ｄｌ），但两者之间差异无显著性（Ｐ＞０．０５）。上述结果提示，生殖道溶脲脲原体感染对附睾功能具有干扰作用，而对精囊腺的功能影响尚缺乏依据，宜进一步探索。     

Insulin growth factors may be implicated in human sperm capacitation

This study was designed to determine whether or not insulin-like growth factor (IGF)-1 and its receptor are present in the human male genital tract. The IGF-1 receptor was found in seminal plasma from fertile and infertile men, but no IGF-1 receptor was observed in sperm from patients with a history of more failed fertilization. The presence of the IGF-1 receptor in the plasma membrane of human sperm is proposed as a future tool for male sterility assessment.     

Semen profile, testicular volume, and hormonal levels in infertile patients with varicoceles compared with fertile men with and without varicoceles

OBJECTIVE: To assess semen analysis, testicular volume, and hormone levels in fertile and infertile patients with varicoceles and fertile men without varicoceles. DESIGN: Retrospective study. SETTING: Academic medical center. PATIENT(S): Patients were divided into three groups: fertile men with varicoceles (n = 79), infertile men with varicoceles (n = 71), and fertile men without varicoceles (n = 217). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Levels of LH, FSH, and total T and testicular volume in fertile and infertile men with varicoceles and fertile controls without varicoceles. RESULT(S): LH (IU/L) and T (ng/dl) levels were not statistically different across the three groups. FSH levels were significantly higher in infertile men with varicoceles (7.8 +/- 7.6 IU/L) than in the fertile men with varicoceles (3.5 +/- 2.1 IU/L) or in fertile men without varicoceles (3.5 +/- 1.9 IU/L). The right testicle was smaller in infertile patients with varicoceles (18.7 +/- 8.3 cm(3)) than in fertile men with varicoceles (25.2 +/- 13 cm(3)) or in fertile men without varicoceles (24.9 +/- 10.7 cm(3)). In addition, the left testicle was smaller in infertile men with varioceles (17.6 +/- 8.9 cm(3)) than in fertile men with varicoceles (21.6 +/- 7.8 cm(3)) or in fertile men without varicoceles (23.4 +/- 8.3 cm(3)). Sperm concentration was lower in infertile men with varicoceles (33.7 +/- 23.3 x 10(6)/mL) than in fertile men with varicoceles (101.8 +/- 76.6 x 10(6)/mL) or in fertile men without varicoceles (111.8 +/- 74.2 x 10(6)/mL). In addition, sperm motility was lower in infertile men with varicoceles (37.2% +/- 23.9%) than in fertile men with varicoceles (53.9% +/- 17.4%) or fertile men without varicoceles (58.9% +/- 15.8%). CONCLUSION(S): Infertile patients with varicoceles have higher levels of FSH, smaller testes, and lower sperm concentration and motility compared with controls with or without varicoceles. No statistical differences were seen in the variables evaluated among the fertile men with incidental varicoceles detected at physical examination and those without varicoceles.     

Levels of cholesterol and phospholipids in freshly ejaculated sperm and Percoll-gradient-pelletted sperm from fertile and unexplained infertile men

Cholesterol and phospholipid levels were determined in individual sperm samples obtained from 20 fertile and 20 unexplained infertile men. The determination was performed on both washed freshly ejaculated sperm and Percoll-gradient-pelletted sperm. Although sperm cholesterol levels in unexplained infertile patients were significantly lower, i.e., 10.6 +/- 1.3 (mean +/- SD) nmol/10(7) freshly ejaculated sperm and 5.4 +/- 0.7 nmol/10(7) Percoll-gradient-pelletted sperm as compared with 19.9 +/- 1.9 nmol/10(7) and 12.6 +/- 1.5 nmol/10(7) for corresponding sperm populations in fertile donors. Motility parameters measured in 10 sperm samples of the two groups of fertile and unexplained infertile men revealed increases in the amplitude of lateral head displacement and decreases in percent of straightness in sperm tracks from unexplained infertile men.     

97例不育男子精浆中微量元素的研究

本文对97例不育男子及13例证实有生育能力男子精浆中的九种微量元素(锌、铁、锰、铜、镍、钾、纳、钙和镁)的浓度用原子吸收分光光度法进行了测定。结果表明:钾、钠和钙在不育与正常男子精浆中的水平几乎一样。不育症患者精浆中的铁、锰和铜浓度高于正常生育力男子精浆中的浓度,其中铁(P<0.05)和锰(P<0.01)的差异具有统计学意义。镍的浓度(P<0.05)显著低于正常男子。具有正常精子密度的不育患者精浆中铁(P<0.05)和锰(P<0.01)显著高于正常男子,锌和铜的浓度也高于正常男子,但无统计学意义。无精患者精浆中的镁(P<0.01)、镍(P<0.05)和铁(P<0.05)浓度明显低于正常男子。镁和镍在不育患者精浆中的浓度随精子密度降低而逐渐降低,但无统计学意义。经迴归处理实验数据,结果表明,锌—钾,锌—钙,锌—镁;钙—钾,钙—镁和镁—钾无论在正常组还是不育组均存在明显的正相关。作者认为结合反映前列腺功能的其他生化指标来测定精浆中的铁、锰、镍及镁的水平有利于对不育症的诊断。     

Ovarian follicular fluid beta-endorphin levels in normal and polycystic ovaries

The possibility of local ovarian production of beta-endorphin prompted us to measure beta-endorphin levels in 19 follicular fluid samples obtained from normal ovaries and compare them with beta-endorphin plasma levels in 19 women with normal ovulation. beta-Endorphin was extracted through Sepharose-treated chromatography columns and assayed with a specific anti-beta-endorphin antibody. Follicular fluid beta-endorphin levels (21.3 +/- 10.8 pg/ml) were significantly higher (p less than 0.01) than the plasma levels (15.5 +/- 3.35 pg/ml). There was no significant correlation between plasma and follicular fluid beta-endorphin concentrations. Follicles greater than 1 cm in size contained more beta-endorphin than follicles less than 1 cm in size (22.7 +/- 3.5 versus 18.7 +/- 4.4 pg/ml, p less than 0.05). Five follicular fluid samples were obtained from polycystic ovaries. The mean beta-endorphin content (45.1 +/- 7.7 pg/ml) in these follicles was significantly higher than that of normal ovaries (p = 0.001). It is concluded that the ovaries produce beta-endorphin and that polycystic ovaries produce more beta-endorphin than normal ovaries.     

Human seminal plasma prolactin-inducible protein is an immunoglobulin G-binding protein

Antisperm antibodies (ASA) are present in 20% of couples seeking treatment for infertility. Antibody-binding proteins in seminal plasma may protect sperm from ASA-induced damage. We have previously isolated several IgG-binding proteins from human seminal plasma using IgG affinity chromatography. Here, we report another such protein which we have identified by amino acid sequencing and confirmed by western blotting to be prolactin-inducible protein (PIP). PIP binds via the Fc fragment of IgG. We have determined the level of PIP in normal seminal plasma to be 3.4 mg/ml (interquartile range 2.0–4.4 mg/ml). We have found there is no difference in the mean level of PIP in seminal plasma from fertile or infertile men regardless of ASA status. PIP was shown to exist in several isoforms in seminal plasma by Western blot. There is a complex pattern of PIP isoform variability in seminal plasma from fertile and infertile men but one multimeric form of PIP was absent from the seminal plasma of men with ASA who were fertile. This may reflect consumption of PIP in these men. The physiological function of PIP remains unknown, but the ability of PIP to bind IgG–Fc suggests PIP may have an immunomodulatory role.     

Immunoglobulin E levels and antisperm antibody titers in infertile couples

Immunoglobulin E (IgE) levels and antisperm antibody titers were determined in samples of serum and seminal plasma from 25 fertile men (Group A), 18 infertile men without measurable immunity to sperm (Group B), and 42 infertile men autoimmune to sperm (Group C), and in samples of serum and cervical and vaginal secretions from 25 fertile women (Group D), 28 infertile women without measurable immunity to sperm (Group E), and 32 infertile women isoimmune to sperm (Group F). Among the men, IgE levels in the serum, measured in international units per milliliter, were elevated in Group C (230 ± 41, mean ± SEM) as compared with Groups B (94 ± 33, P < 0.05) and A (55 ± 8, P < 0.001). In contrast, IgE levels in the seminal plasma in Group C (180 ± 44) were not significantly different from those in Group B (48 ± 21), but were higher than those in Group A (8 ± 2, P < 0.05). In the women, serum IgE levels were higher (P < 0.001) in Group F, with isoimmunity to sperm (472 ± 55), than in Groups E (219 ± 32) and D (76 ± 16). Wives of autoimmune husbands had somewhat, though not significantly, higher serum IgE levels (406 ± 55), than had wives of nonautoimmune husbands (247 ± 97). These results provide evidence for an elevated IgE response in subjects with significantly elevated antisperm antibody titers.     

Seminal prolactin and its relationship to sperm motility in men

Semen assessment and levels of serum and seminal plasma prolactin (PRL) were determined in 81 men. In subjects with both normal sperm concentrations and normal sperm motility, the levels of serum and seminal plasma PRL were 14.7 +/- 1.48 and 10.0 +/- 1.05 ng/ml (mean +/- standard error of the mean, SEM, P less than 0.05), respectively. This difference is not observed either in subjects with polyzoospermia with normal sperm motility, or in those with oligozoospermia. Serum PRL was higher in azoospermia and also in subjects with lower levels of seminal citric acid. Seminal plasma PRL was directly related to sperm motility (r = 0.70, P less than 0.01) and inversely related to sperm concentration (r = -0.42 P less than 0.05). Seminal PRL was increased in subjects with higher levels of seminal citric acid and decreased in subjects with lower levels of corrected seminal fructose. Serum and seminal plasma PRL did not change significantly in subjects with different concentrations of serum testosterone.     

ELISA法检测不育男子精浆中抗精子IgG和IgA

将精子经Tritonx－100处理，冷冻高速离心后，经抗人全血清-SephadexG－75亲和柱层析分离，提取分子量为59KD人精子膜蛋白作为抗原，经ELISA间接法对20例生育男子和50例不育男子精浆中抗精子IgG和IgA进行了测定。结果显示：生育男子精浆中抗精子IgG为阴性；抗精子IgA阳性率为5％。不育男子精浆中抗精子IgG和IgA阳性率分别为10％、30％；抗精子IgG和IgA均为阳性者3例，均为阴性者33例；抗精子IgG阳性而IgA阴性者2例；抗精子IgA阳性而IgG阴性者12例。不育组与生育组间抗精子IgG阳性率无显著性差异（P＞0．05）；而IgA阳性率间则有显著性差异（P＜0．05）。不育组抗精子IgG和IgA阳性率间有极显著性差异（P＜0．01）。本文利用ELISA法对精浆中抗精子抗体的分类及可能来源进行了讨论。     

Plasma immunoreactive beta-endorphin, ACTH and cortisol concentrations in mothers and their neonates immediately after delivery--their relationship to the duration of labor

In 29 cases of vaginal delivery with normal outcome and 4 cases of cesarean section, the concentrations of beta-endorphin, ACTH and cortisol were determined in maternal venous and umbilical venous plasma immediately postpartum. According to duration of labor and mode of delivery the cases examined were classified into three groups: Group A (18 cases) = vaginal delivery of less than 10 hours' duration, Group B (11 cases) = vaginal delivery of more than 10 hours' duration of labor, Group C (4 cases) = cesarean section under general anesthesia. With the exception of one, the deliveries took place at term. The 33 neonates were in a very good clinical state 5 minutes after parturition (11 Saling points as median value). For measurement of the hormone concentrations radioimmunoassays were used. In Group a the mean beta-endorphin concentration in maternal plasma amounted to 150.9 +/- 16.3 pg/ml, that in neonatal plasma to 239.2 +/- 23.5 pg/ml (means +/- SEM). In Group B plasma beta-endorphin, both maternal and neonatal, was slightly higher than in Group A: 153.0 +/- 12.0 pg/ml (maternal) and 260.9 +/- 37.1 pg/ml (neonatal). The differences between maternal and neonatal beta-endorphin levels were statistically significant: Group A p less than 0.01, Group B p less than 0.05; chi 2-test. The mean ACTH concentrations in the plasma of the newborn infants were also found to be considerably higher compared with those in the plasma of their mothers: Group A 78.2 +/- 16.5 pg/ml (maternal) and 98.0 +/- 23.3 pg/ml (neonatal); Group B 98.0 +/- 20.1 pg/ml (maternal) and 165.8 +/- 39.6 pg/ml (neonatal).(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum and seminal plasma prolactin concentrations in men with normospermia, oligospermia, or azoospermia

Semen analyses were performed and serum and seminal plasma prolactin (PRL) concentrations were determined in 165 samples from 120 men seen with their wives because of infertility. The mean (+/- standard deviation) serum and seminal plasma PRL concentrations were 6.5 +/- 3.3 and 7.5 +/- 3.1 ng/ml, respectively. The mean concentrations of PRL in serum and seminal plasma were similar in groups of men divided by sperm concentration. Seven men had an increased serum PRL concentration. Three of these 7 men had sperm concentrations less than 20 million/ml and none of these 7 men had an increased seminal plasma PRL concentration. Four men had an increased seminal plasma PRL concentration; the serum PRL concentration, sperm concentrations, and motilities were normal in all 4. No man had a decreased serum or seminal plasma PRL concentration. Increased serum PRL concentrations were found infrequently and the increase was slight (23.2 ng/ml or less). Seminal plasma PRL concentrations were related directly to sperm concentrations and motilities, relationships that were statistically significant.