Structural and biological characterization of a novel spermicidal vanadium(IV) complex: bis(pi-cyclopentadienyl)-N,N-diethyl dithiocarbamato vanadium(IV) tetrafluoro borate, [VCp2(DeDtc)](BF4)

In a systematic search for vanadocene complexes with sperm immobilizing activity as a new class of contraceptive agents, we identified V(eta 5-C5H5)2((C2H5)2 NCS2)(BF4) (=[VCp2(DeDtc)](BF4)) as the most potent and stable spermicidal compound. Here we report the detailed biologic and physicochemical characterization of this lead spermicidal compound by computer-assisted sperm analysis, electron paramagnetic resonance spectroscopy, electrochemistry, and X-ray crystallography. [VCp2(DeDtc)](BF4) crystallized in the monoclinic space group P2(1)/c, with unit cell dimensions a = 7.0877(4) A, b = 22.2881(14) A, c = 11.8021(7) A, beta = 94.107(1) degree, V = 1859.6(2) A3. The final structure of [VCp2(DeDtc)](BF4) had an R factor of 0.0581 for 3191 independent reflections. The two sulfur atoms of the dithiocarbamate and centroids of the cyclopentadienyl rings in this vanadocene complex with unique contraceptive potential occupy four tetrahedral--like coordination sites about the central metal atom.

Dose-response effects of gramicidin-D, EDTA, and nonoxynol-9 on sperm motion parameters and acrosome status

Previous reports showed that gramicidin-D (G-D), a polypeptide with antiviral and antimicrobial properties, nonoxynol-9 (N9), a common spermicidal detergent, and EDTA, a Ca-Mg chelating agent, inhibited sperm motility and cervical mucus penetration. The purpose of this study was to determine the dose-response effects of G-D, N9, EDTA and G-D + EDTA on sperm motion parameters and acrosome status. Semen specimens from known fertile donors were subjected to computer-assisted semen analysis of motility, path velocity, progressive velocity, and hyperactivation prior to and after incubation with varying concentrations of gramicidin-D, EDTA and nonoxynol-9. Each specimen was also prepared for acrosome status using rhodamine isothiocyanate conjugated pisum sativum agglutinin (RITC-PSA). There was a significant decrease in motility by G-D, EDTA, G-D + EDTA, and N9 at all doses as compared to the fresh specimen. N9 completely immobilized all sperm at each dose. Progressive velocity and path velocity also decreased in a dose-response manner. Sperm hyperactive motility also significantly decreased in all groups. The majority of sperm remained acrosome intact following exposure to all doses tested, whereas N9 resulted in complete breakdown/release of the acrosomal contents. This study confirms previous reports that G-D, EDTA, and N9 significantly impair sperm motility and motion parameters. The effective 100% inhibitory concentration was seen only with N9, whereas G-D, EDTA, and G-D + EDTA resulted in incomplete impairment of sperm motion parameters. At the concentrations used, N9 demonstrated potent spermostatic activity. Gramicidin-D and EDTA should be further studied for their potential contraceptive spermostatic activity.

Alteration of human sperm kinematics in cervical mucus due to nonoxynol-9

Traditional endpoints of the double-ended test (DET), a contraceptive screening assay used to evaluate the ability of a compound to permeate cervical mucus and inhibit sperm progression, ignore important information about sublethal effects upon sperm cells. Improved contraceptive agents may capitalize on such sublethal aspects. This study utilized a DET testing protocol that included measurement of human sperm motion characteristics as an indicator of cell function within spermicide-exposed human mucus. The currently available spermicide nonoxynol-9 (N9) was used as the test compound and was dissolved in two different delivery solutions, deionized (DI) water and saline, to evaluate the effects of the osmolarity and pH of the delivery vehicle on test results. The N9-water treatment demonstrated significantly greater activity than the N9-saline treatment in terms of all measured variables, exhibiting an apparent "biopermeation" distance approximately 3 mm further into the mucus. The DI water control treatment displayed less activity than N9-saline in terms of the vanguard penetration distance, but comparable or greater activity in terms of inhibiting kinematic variables. The saline control treatment had no effect in terms of any measured variable. Dose responses to N9 of sperm in mucus were inferred from DET results combined with direct measures of N9 diffusion. These were compared to dose responses to N9 of seminal sperm, indicating that N9 inhibits sperm motion at lower concentrations in mucus than in semen.

Synergistic effect of gramicidin and EDTA in inhibiting sperm motility and cervical mucus penetration in vitro

Gramicidin, a linear polypeptide with antiviral and antimicrobial properties, was compared in vitro with a commonly used spermicidal detergent-nonoxynol-9 (N9). The inhibition of sperm functions was evaluated by computer-assisted semen analysis (CASA) for sperm motility, in cervical mucus penetration assay, and by colorimetric tetrazolium salt and lactate dehydrogenase release assays routinely employed for testing the toxicity of drugs. The effective 100% inhibitory concentration (IC100) of gramicidin in a 2-min sperm immobilization assay by CASA was equal to 4 micrograms/ml, whereas IC100 of N9 was equal to 200 micrograms/ml. The presence of 0.1% of chelating agent, EDTA, reduced IC100 of gramicidin to 10 ng/ml, while less than a twofold enhancement in N9 activity was observed upon combination with EDTA. Likewise, the gramicidin/EDTA combination was 100,000 times more potent than N9/EDTA in the sperm penetration assay. Quantitative toxicity tests confirmed that gramicidin is a potent spermostatic rather than spermicidal agent. Further development of a gramicidin/EDTA formulation is warranted as a nontoxic topical contraceptive with activity against viral and microbial sexually transmitted diseases (STDs).

Zinc acetate and lyophilized aloe barbadensis as vaginal contraceptive

Twenty samples of fresh ejaculate, donated by healthy volunteers ranging in age from 20-30 years, were obtained from the Center for Fertility & Cryobiology, University of Missouri, Columbia, Missouri. Average semen volume was 2.49 ml; average sperm motility was 71.32%; and average sperm density was 113.71 x 10(6) /ml. Testing for spermicidal effectiveness of a 1% concentration of zinc acetate, zinc sulfate, zinc chloride, and zinc gluconate proved that only zinc acetate was spermicidal. It appears this is due to the acetate in zinc acetate which may decrease oxygen utilization by sperm. Zinc acetate in vitro was antiviral while lyophilized aloe barbadensis was not. Lyophilized aloe barbadensis at concentrations of 7.5% and 10% proved to be spermicidal due to the multiple micro elements (boron, barium, calcium, chromium, copper, iron, potassium, magnesium, manganese, phosphorus, and zinc) which were toxic to the tail causing instant immobilization. The two compounds did not irritate or cause ulceration of rabbit vaginal epithelium. These results suggest the possibility of using zinc acetate and lyophilized aloe barbadensis as a new, effective and safe vaginal contraceptive.

Spermicidal activity of Magainins: in vitro and in vivo studies

Spermicidal efficacy of two synthetic antimicrobial peptides, viz. Magainin-A (Mag-A) and Magainin-G (Mag-G), have been studied under in vitro condition using rat and human spermatozoa. The data showed that sperm motility was inhibited with various concentrations of Magainins at different intervals ranging from 20 to 480 seconds as compared to controls. The minimum concentration of Mag-A required to immobilize spermatozoa (40-60 x 10(6)/ml of saline) within 20 seconds was found to be 100 micrograms in rat and 200 micrograms in human. The action of Mags on sperm motility was observed to be dose-dependent. The activity of Mag-A was significantly (P < 0.05) higher than Mag-G (P < 0.05). The in vivo studies in rats indicated that Mag-A when applied intravaginally, on the day of estrus, at the dose level of 200 micrograms, for five consecutive estrous cycles, induced no abnormalities either in the length of estrous cycle or in morphology of vaginal epithelial cells. When Mag-A was applied intravaginally before mating on the proestrusestrus day, complete arrest of sperm motility with 200 micrograms concentration was observed and none of these treated females conceived after the mating. In view of these facts, it is suggested that Mag-A, having anti-bacterial, anti-viral, anti-fungal and spermicidal activities, could be a potent vaginal contraceptive.

Comparative in vitro spermicidal activity of chelating agents and synergistic effect with nonoxynol-9 on human sperm functionality

Nonoxynol-9 (N-9), a nonionic surfactant, exerts both spermicidal and anti-viral activities and is the most widely used spermicide. Although N-9 has been regarded as an efficient spermicidal agent for barrier contraception, it has been reported to cause vaginal irritation and allergic vaginitis, and its spermicidal action in the vaginal mucus may be limited. To address these problems, the spermicidal activity of several chelating agents against human semen and their synergistic effect on the spermicidal activity of N-9 were evaluated using computer-assisted semen analysis and a cervical mucus penetration test. Carbopol 934P, chosen as a polymer base for dispersion of N-9 and chelating agent, was also evaluated for its potential spermicidal activity. Chelating agents, such as ethylenediaminetetraacetic acid (EDTA), ethylene bis(oxyethylenenitrilo)tetraacetic acid, and gramicidin, had spermicidal activity against human sperm at the tested concentration range and exerted spermicidal activity within mucus, impeding sperm penetration to the extended cervical space. A synergistic effect was shown between N-9 and EDTA on sperm motility. In dose-response curves, 0.1% EDTA significantly increased binding affinity constant and spermicidal potency of N-9 and reduced the concentration of N-9 at which 50% of the maximum response was observed from 144.5 to 66.4 (micrograms/mL). A synergistic effect was also shown between EDTA and carbopol 934P polymer on inhibition of sperm penetration through the cervical mucus. Therefore, EDTA can be used as a supplementary agent and potentiator for N-9. Development of a carbopol 934P-based drug delivery system for dual controlled release of N-9 in combination with chelating agents seems to be a promising approach for increasing the efficacy of fertility control.

Complementary effects of propranolol and nonoxynol-9 upon human sperm motility

The inhibitory effects of nonoxynol-9, DL- and D-propranolol upon human sperm motility were determined in vitro. All three compounds were capable of causing complete cessation of sperm movement. However, greater efficacy was achieved using combinations of nonoxynol-9 and propranolol, suggesting a complementary interaction between these compounds. Investigations of the mechanism of action of propranolol revealed that an influx of calcium accompanied the loss of motility. However, since incubation in the absence of calcium enhanced the spermicidal effects of this compound, it was concluded that this calcium influx did not constitute the primary means by which motility was disrupted. Low doses of propranolol, which did not affect motility, were found to inhibit the capacity of human spermatozoa for sperm-oocyte fusion.

Acrosin inhibitor, 4'-acetamidophenyl 4-guanidinobenzoate, an experimental vaginal contraceptive with anti-HIV activity

Serine proteases are involved in a wide variety of seemingly unrelated physiological functions including capacitation of the spermatozoa and potentiation of human immunodeficiency virus (HIV) infection. The experimental vaginal contraceptives derived from 4-guanidinobenzoic acid act through inhibition of acrosin--a serine protease from the sperm. The serial ten-fold dilutions of 4'-acetamidophenyl 4-guanidinobenzoate (AGB) were tested in vitro for the effect against HIV infection by assaying the suppression of de novo p24 synthesis in virus-inoculated MT-4 T lymphocytes. The results reveal that complete inhibition of HIV occurred at 100 micrograms/ml--a dose corresponding to previously reported concentrations responsible for preventing fertilization in rabbits. These findings suggest that serine protease inhibitors and in particular the guanidinobenzoates, reported to be up to 100-fold more potent and less irritating than nonoxynol-9, can be potentially operative against sexual transmission of HIV.

Effects of vasectomy on the epididymis

Common principles can be discerned in the response of the epididymis to vasectomy, despite species differences. Increases in the size and number of lysosomes are the most frequent changes in the epididymal epithelium. The presence or absence of additional alterations such as changes in the height of the epithelium may be related to variations in distensibility of the vas deferens and epididymis. Direct measurements by micropuncture of epididymal and seminiferous tubule hydrostatic pressure indicate that, contrary to dogma, increased pressure in the distal epididymis after vasectomy is not generally transmitted to the seminiferous tubules. The epididymal interstitium shows microscopic changes indicative of chronic inflammation, with infiltration of macrophages, lymphocytes, and plasma cells, and rats with these lesions have higher antisperm antibody levels than animals lacking epididymal changes. Macrophages and neutrophils may enter the duct through the epididymal epithelium, at sites of rupture of the duct, and in the efferent ductules. Cyst-like spermatic granulomas occur in virtually all species where the epididymis or vas deferens ruptures with escape of spermatozoa. The sites and timing of granuloma formation may depend on the mechanical properties of the tract in different species, and they are probably important in the immune response to vasectomy. Postvasectomy sera in Lewis rats recognize a consensus repertoire of dominant autoantigens that closely resembles the antigens bound by sera from rats immunized with isologous spermatozoa. There are multiple routes for disposal of the sperm that continue to be produced after vasectomy.

Anti-sperm and anti-ovum vaccines: the selection of candidate antigens and the outcome of preclinical studies

A clear conceptual basis for anti-sperm and other modes of immunological birth control exists in spite of the limited basic research done on surface antigens of sperm or egg. In the normal physiological condition, the immune system does not respond to sperm, egg or fetus. Compared with anti-egg or anti-fetus immunocontraception, an anti-sperm vaccine has two theoretical advantages. First it would work in both males and females; second, it would not raise problems of autoimmunity in the female if a sperm-specific protein is used. However, for the development of such contraceptive vaccines the following scientific questions need to be resolved: (1) what surface protein to use as an antigen; (2) what adjuvant to use in humans for an anti-fertility vaccine; (3) how to maintain a high titre; (4) how the contraceptive effect will be terminated; and (5) what are the potential side-effects.

Quantification of the in vitro activity of some compounds with spermicidal activity

The in vitro spermicidal activity of the commonly used surfactant spermicides and the antiseptic chlorhexidine, were quantified in a statistically reproducible manner, using donor semen and image capture analysis. The spermicidal activity was expressed as the ED50 under defined assay conditions. Using these parameters, the order of spermicidal activity was: Menfegol > nonoxynol-9 approximately benzalkonium chloride > sodium docusate > chlorhexidine. These differences were statistically significant.

The immobilization of all spermatozoa in vitro by bitter lemon drink and the effect of alkaline pH

This study investigated the effects of increase in temperature and in pH of Coca-Cola, Afri-Cola, Pepsi-Cola and Krest bitter lemon drinks ("soft drinks") produced in Nigeria on the in vitro motility of spermatozoa. Semen was collected from 7 men, average age 28 years, of proven fertility, after 5 days' abstinence from sexual intercourse. The temperature and pH of the drinks were adjusted from 22 degrees C (room) to 37 degrees C, and pH 2.4 (acid) to 7.5 (alkaline), respectively. The mean % motility of spermatozoa in the adjusted and in the unadjusted drinks was compared for significant differences at the 1% level using the student's t-test. The results showed no significant differences in mean % motility in the drinks at 22 degrees C and at 37 degrees C. The mean % motility in all the drinks, except Coca-Cola, was significantly greater at alkaline than at acid pH; for Coca-Cola, motility was significantly greater at acid than alkaline pH. Of the drinks, Krest bitter lemon (unadjusted) immobilized all spermatozoa within 1 minute of addition.

CONCLUSION

i) alkalinity decreases the spermicidal action of all drinks except Coca-Cola, and ii) Krest bitter lemon may achieve very high efficacy if used as post-coital douche, especially in the impoverished, densely populated Third World.

Effects of the prostanoid receptor antagonist, di-4-phloretin phosphate, upon human sperm motility

The inhibitory effects of the prostanoid receptor antagonist, di-4-phloretin phosphate (DPP), upon washed human sperm motility were determined in vitro (up to 60 min of incubation). Concentrations tested were: 0.001, 0.01, 0.1, 0.25, 0.5, 2.5, 5.0 and 10.0 mM. All concentrations of DPP investigated caused cessation of sperm movement (percentage motility and average forward velocity) and the antimotility effect was essentially irreversible. The concentrations producing 50% inhibition were: percentage motility--1.31 +/- 0.56 mM (mean +/- SEM) and average forward velocity--1.95 +/- 0.68 mM. The mode of antimotility action appears to be multi-faceted. At high (10 mM) and intermediate (2.5 mM) concentrations, changes in fluidity of sperm plasmalemma (hypoosmotic swelling test) and loss of viability (nigrosin-eosin stain technique) constitute the primary means by which motility was disrupted. In contrast, these two parameters of motility remained unaltered at a lower concentration (0.25 mM) of DPP, and the mechanism precipitating the antimotility effect may involve mobilization of stored calcium ions and modulation of cyclic AMP levels.

[Application of a trans-membrane migration method in the study of human sperm motility: a review]

Transmembrane migration method is a bioassay specifically designed to study drug effect on human sperm motility. It was first used in the study of sperm immobilizing agents which have a membrane stabilizing effect. Then it was used to investigate the relationship between calcium ion and sperm motility. Recently, this method has been used to screen drugs that stimulate sperm motility. It has also been modified for the study of porcine sperm motility. Computer assisted semen analysis showed that the transmembrane migration method is most suitable for studying drug effect on rapid and straight-forward motility of sperm.

Sperm immobilizing effect of triterpene saponins from Acacia auriculiformis

A mixture of two partially triterpenoid saponins (Tg), isolated from Acacia auriculiformis was tested for sperm immobilizing activity by using in vitro system. The lowest concentration (ED) required for an obvious immobilization of human sperm by using a modified Sander-Cramer test was found to be 0.35 mg/ml in physiological saline. The ability of the compound as a sperm immobilizing agent was compared with that of Triton X-100 and found to be more potent. Cervical mucus penetration test was also performed and the ED successfully prevented sperm entry in human cervical mucus. Supra-vital staining with eosin-nigrosin indicated death of the treated sperm. Electron microscopic study of Tg-treated sperm showed plasma membrane disintegration and dissolution of acrosomal cap which is presumably the cause for the spermicidal effect of the saponins. No permanent lesion was observed after application of 1.25 mg/ml Tg solution in physiological saline to the eye of rabbits for ten consecutive days.

Studies on the in vitro spermicidal activity of synthetic magainins

Two synthetic magainins A and G are shown to have spermicidal activity. Transmission electron microscopic micrographs show that both magainins alter the plasma membranes of sperm and that these actions are rapid. Further studies will better delineate the contraceptive potential of synthetic magainins.

Comparative effects of (+)-propranolol and nonoxynol-9 on human sperm motility in-vitro

Using the modified transmembrane migration method to measure sperm motility, it was shown that the surfactant nonoxynol-9 alone, was twice as potent as (+)-propranolol alone as a spermicidal agent. Addition of (+)-propranolol to nonoxynol-9 shifted the dose-response curve to the left of the curves for either component alone, and a surprising synergistic action was evident. These observations may form the basis for the development of a new advantageous topical contraceptive combination product.

The inhibitory effect of gossypol on human sperm motility: relationship with time, temperature and concentration

The inhibitory effect of gossypol acetic acid on human sperm motility was studied with a transmembrane migration method. Gossypol decreased sperm motility after it had been incubated with semen for more than 15 min. However, when sperm motility was evaluated immediately after semen had been mixed with gossypol, no inhibitory effect could be found. We consider that the sperm immobilizing potency of gossypol is much less than our previously studied sperm immobilizing agents. It is unlikely that gossypol can be developed as a vaginal spermicide. The importance of time course in the pharmacological study of sperm motility is emphasized in this study.

The spermicidal potency of Coca-Cola and Pepsi-Cola

The inhibitory effect of Old Coke, caffeine-free New Coke, New Coke, Diet Coke and Pepsi-Cola on human sperm motility was studied with a trans-membrane migration method. None of them could decrease sperm motility to less than 70% of control within one hour. A previous study which claimed a marked variation of spermicidal potencies among different formulations of Coca-Cola could not be confirmed. Even if cola has a spermicidal effect, its potency is relatively weak as compared with other well-known spermicidal agents.

Studies on the male antifertility agent gossypol acetic acid. VII. Effect of motility stimulated factors on the revival of human spermatozoal motility after gossypol treatment in vitro

Human spermatozoa were incubated with gossypol acetic acid (100 micrograms/1 X 10(6) spermatozoa/ml) at 37 degrees C for 30 min. The drug treatment inhibited the spermatozoal motility significantly. Washing of the spermatozoa, after gossypol treatment, did not effect their motility. A partial revival in the motility of the spermatozoa was observed when gossypol treated spermatozoa were incubated, after washing, with motility stimulating factors, e.g. theophylline, dibutyryl-cAMP and Kallikrein.

A comparison of the effects of nonoxynol-9 and chlorhexidine on sperm motility

The effects of Nonoxynol-9 and chlorhexidine on sperm motility were compared using the objective Transmembrane Migration Ratio method. These agents were found to be of similar potency in inhibiting sperm motility. The concentrations which reduced sperm motility by 50% (EC50) were 0.205 mg/ml for Nonoxynol-9 and 0.215 mg/ml for chlorhexidine. The implications of these findings in relation to the comparison of the effects of drugs on sperm motility and the development of new contraceptive agents are discussed.

Hydrolysis of phospholipid monolayers by human spermatozoa. Inhibition by male contraceptive gossypol

Monomolecular films of phospholipid were used to study the interaction of intact human spermatozoa with model membranes. Exclusively with negatively charged phosphatidylglycerol monolayers rapid penetration of spermatozoa into the monolayer with subsequent hydrolysis of the lipid was triggered by the addition of 5 mM calcium into the medium. The results suggest the localization of a calcium-dependent phospholipase A2 at the outer acrosomal or plasma membrane of human spermatozoa with its active site exposed to the external environment. Preincubation of the cells with 100 microM gossypol completely abolished the ability of human spermatozoa to hydrolyze or penetrate monolayers of phosphatidylglycerol. The inhibition of the phospholipase activity by gossypol may contribute to the unknown contraceptive mechanisms of this non-steroidal male antifertility agent.

Interaction of 14 C-gossypol with human sperm

Gossypol, a bis-sesquiterpene, suppresses spermatogenesis and inhibits sperm motility. The direct interaction of gossypol with human sperm was investigated. Conditions influencing the interaction of 14c-gossypol (radiolabeled on the aldehyde group with specific activity of 3.33 x 10 5 dpm per micromole) with human sperm reached saturation rapidly. Within 1 minute of exposure of motile sperm to 10 uM radiolabeled gossypol at 37 degrees Centigrade, the cincorporation of 14c-gossyol was 17 at 35% at densities of 2.5 x 106 and 8.6 x 106 per ml, respectively. Immobile sperm prepared by heating at 60 degrees Centigrade for 10 minutes incorporated the same amount of 14c-gossypol as motile sperm. Uptake of 14c-gossypol was slightly greater at 37 degrees Centigrade than at 4 degrees Centigrade, and under acidic conditions. To identify the sperm membrane components interacting with gossypol radiolabeled sperm were treated with the following 3 solutions to solubilize the membrane proteins: 0.1% Triton X-100; 1 M urea, 5 mM EDTA in 19mM Tris-HC1, pH 8.3; and 20% sodium doydecyl sulfate (SDS), 0.1M 20mercaptoethanol. The amount of radiolabeled proteins solubilized with respective media were 11, 23, and 67% with specific activities of 1.8 x 103, 2.1 x 105, and 0.3 x 103 cpm per mg protein. The radiolabeled substances solubilized with SDS, mercaptoethanol reagent were separated by gel filtration on Sephadex G-100 column. 3 peaks of radioactivities corresponding to molecular weights of approximately 100, 35, and 25 KD were eluted. The highest radioactivity was found with the 100 KD fraction. The interaction of gossypol with sperm membrane proteins is an early event, followed by inhibition of sperm motility.

Local anaesthetic effect of antiarrhythmic drugs and human sperm immobilization: mechanism and application of the interrelationship

Sperm immobilizing activity of three class I antiarrhythmic drugs, quinidine, procainamide, mexiletine, one adrenoceptor blocking drug, labetalol and one calcium channel blocking drug, diltiazem was measured with a trans-membrane migration method. All these drugs immobilized human sperm. Local anaesthetic effect is the underlying mechanism for these drugs to inhibit sperm motility. Sperm immobilization could be a screening test for the local anaesthetic effect of antiarrhythmic drugs.

Sperm immobilizing potency of amitriptyline and imipramine: measured with transmembrane migration

The inhibitory effect of amitriptyline and imipramine on human sperm motility was measured in vitro with a transmembrane migration method. The EC50 for amitriptyline and imipramine were 170 microM and 160 microM respectively. They were more potent than any other drug that had been tested on this pharmacological model. Transmembrane migration method was less sensitive than turbidimetric method to detect the sperm immobilizing effect of drugs.

Vaginal contraception with gossypol: a clinical study

A clinical study concerning the vaginal contraceptive efficacy of gossypol acetic acid was performed. Fifteen women who had undergone tubal sterilization volunteered for the study. The effect of vaginal gossypol-containing gel on spermatozoa was determined by postcoital tests performed in subjects without and after using gossypol gel. After gossypol application, the number of spermatozoa found in cervical mucus was greatly decreased and, in eleven of the fifteen women, all spermatozoa seen were immobilized. In four cases a few poorly motile spermatozoa were seen but they showed no forward progression. We have previously reported that gossypol has an inhibitory effect on herpes simplex virus type 2 in vitro. This anti-viral property of gossypol makes it particularly attractive as a topical barrier contraceptive. The present study shows that gossypol is also promising as a vaginal contraceptive agent in human in vivo experiments.

Gossypol as oral contraceptive for male: trial case report

Gossypol has been used as oral contraceptive for man in People's Republic of China. There are also some reports of studies in which gossypol acetic acid is used in animal experiments. In this study we used tablet preparation of gossypol, which is actually used as oral contraceptive for male in People's Republic of China, on a volunteer. The administration of 20 mg/day gossypol tablets for 19 days resulted in a tendency of decreasing sperm density and total sperm count, but had no effect on serum LH, FSH, PRL or testosterone. Furthermore, the volunteer had no complaints of side effects and his general laboratory findings were normal. Ten days after the termination of gossypol administration, sperm density returned to its preadministrative level. Our study suggests gossypol may be effective as a male oral contraceptive with no acute side effect.

Influence of lipid solubility on the sperm immobilizing effect of beta-adrenoceptor blocking drugs

1 Sperm immobilizing effects of five beta-adrenoceptor blockers were measured on six human semen samples with a trans-membrane migration method. 2 The concentrations which decreased sperm motility to 50% of control (ED50) were 0.8, 4.2, 6.2, 11.0 and 33.0 mM for propranolol, oxprenolol, metoprolol, acebutolol and sotalol respectively. 3 There was a linear correlation between the log values of ED50 and the log partition coefficients of these beta-adrenoceptor blockers. 4 Because the lipid solubility determines the sperm immobilizing potencies of beta-adrenoceptor blockers, we support the theory that beta-adrenoceptor blockers inhibit sperm motility by stabilizing the cellular membrane. 5 The clinical implication of this finding is that more lipid soluble drugs are likely to have more interference on sperm function, at least when they are used locally.