Antispermatogenic action of gossypol in men

Non-hormonal Contraception: Current and Emerging Targets

There is a global need for effective, reversible contraception. While female hormonal options meet these criteria and are widely used, they are associated with side effects and may be contraindicated for women with certain pre-existing medical conditions. To meet the needs of women who cannot take or cannot tolerate these medications, several non-hormonal options are currently available, including copper intrauterine devices (IUDs), spermicides, and a new vaginal pH modulator (VPM). Several other options are currently in development, including vaginal rings, gels, and vaginally administered anti-sperm antibodies. For men, there are currently no contraceptive options available aside from condoms and vasectomy; however, several non-hormonal contraceptives targeting various aspects of sperm production and/or sperm function are currently under investigation. In this narrative review, we will discuss both the non-hormonal contraceptive methods currently available for women, as well as emerging non-hormonal medications, compounds, and devices for both genders.

Sperm Vitality and Necrozoospermia: Diagnosis, Management, and Results of a Global Survey of Clinical Practice

Sperm vitality testing is a basic semen examination that has been described in the World Health Organization (WHO) Laboratory Manual for the Examination and Processing of Human Semen from its primary edition, 40 years ago. Several methods can be used to test sperm vitality, such as the eosin-nigrosin (E-N) stain or the hypoosmotic swelling (HOS) test. In the 6th (2021) edition of the WHO Laboratory Manual, sperm vitality assessment is mainly recommended if the total motility is less than 40%. Hence, a motile spermatozoon is considered alive, however, in certain conditions an immotile spermatozoon can also be alive. Therefore, the differentiation between asthenozoospermia (pathological decrease in sperm motility) and necrozoospermia (pathological decrease in sperm vitality) is important in directing further investigation and management of infertile patients. The causes leading to necrozoospermia are diverse and can either be local or general, testicular or extra-testicular. The andrological management of necrozoospermia depends on its etiology. However, there is no standardized treatment available presently and practice varies among clinicians. In this study, we report the results of a global survey to understand current practices regarding the physician order of sperm vitality tests as well as the management practices for necrozoospermia. Laboratory and clinical scenarios are presented to guide the reader in the management of necrozoospermia with the overall objective of establishing a benchmark ranging from the diagnosis of necrozoospermia by sperm vitality testing to its clinical management.

Rising trends towards the development of oral herbal male contraceptive: an insight review

Background

Acknowledging population control to be an essential step for global health promotes wide research study in the area of male contraception. Although there are a great number of synthetic contraceptives available in the market, they have plenty of adverse effects. Different potential strategies for male contraception were investigated over a long period time consisting of hormonal, chemical, and immunological interventions, although these methods showed good antifertility results with low failure rates relative to condoms.

Main text

This review is based upon the concept of herbal contraceptives which are an effective method for controlling the fertility of animals and humans. This review has highlighted herbal medicinal plants and plant extracts which have been reported to possess significant antifertility action in males. The review considers those plants which are used traditionally for their spermicidal and antispermatogenic activities and imbalance essential hormones for fertility purposes and plants with reported animal studies as well as some with human studies for antifertility effect along with their doses, chemical constituents, and mechanism of action of the antifertility effect of the plants. This review also explains the phases of sperm formation, hormone production, and the mechanism of male contraceptives.

Conclusion

As far as the relevance of the current review is discussed, it might be quite useful in generating monographs on plants and recommendations on their use. A lot of the plant species listed here might appear promising as effective alternative oral fertility-regulating agents in males. Therefore, significant research into the chemical and biological properties of such less-explored plants is still needed to determine their contraceptive efficacy and also to possibly define their toxic effects so that these ingredients can be utilized with confidence to regulate male fertility. The new inventions in this field are necessary to concentrate on modern, more potent drugs with less harmful content and that are self-administrable, less costly, and entirely reversible.

Latheef S, Sharun K, Khurana SK, K. A, Tiwari R, Bhatt P, K. V, Chaicumpa W. Role of Antisperm Antibodies in Infertility, Pregnancy, and Potential forContraceptive and Antifertility Vaccine Designs: Research Progress and Pioneering Vision

Sperm of humans, non-human primates, and other mammalian subjects is considered to be antigenic. The effect of changes in autoimmunity on reproductive cells such as spermatozoa and oocytes play a critical but indistinct role in fertility. Antisperm antibodies (ASAs) are invariably present in both females and males. However, the degree of ASA occurrence may vary according to individual and gender. Although the extent of infertility due to ASAs alone is yet to be determined, it has been found in almost 9-12% of patients who are infertile due to different causes. Postcoital presence of spermatozoa in the reproductive tract of women is not a contributory factor in ASA generation. However, ASA generation may be induced by trauma to the vaginal mucosa, or by anal or oral sex resulting in the deposition of sperm inside the digestive tract. It is strongly believed that, in humans and other species, at least some antibodies may bind to sperm antigens, causing infertility. This form of infertility is termed as immunological infertility, which may be accompanied by impairment of fertility, even in individuals with normozoospermia. Researchers target ASAs for two major reasons: (i) to elucidate the association between ASAs and infertility, the reason ASAs causes infertility, and the mechanism underlying ASA-mediated infertility; and (ii) to assess the potential of ASAs as a contraceptive in humans in case ASAs influences infertility. Therefore, this review explores the potential application of ASAs in the development of anti-spermatozoa vaccines for contraceptive purposes. The usefulness of ASAs for diagnosing obstructive azoospermia, salpingitis, and oligoasthenoteratozoospermia has been reviewed extensively. Important patents pertaining to potential candidates for spermatozoa-derived vaccines that may be utilized as contraceptives are discussed in depth. Antifertility vaccines, as well as treatments for ASA-related infertility, are also highlighted. This review will address many unresolved issues regarding mechanisms involving ASAs in the diagnosis, as well as prognoses, of male infertility. More documented scientific reports are cited to support the mechanisms underlying the potential role of ASA in infertility. The usefulness of sperm antigens or ASAs (recombinant) in human and wild or captive animal contraceptive vaccines has been revealed through research but is yet to be validated via clinical testing.

[Necrozoospermia: From etiologic diagnosis to therapeutic management]

This review describes necrospermia, its diagnosis, causes and management. Sperm vitality is commonly assessed in the laboratory of reproductive biology, with the eosin test or with the hypo-osmotic swelling test. Necrospermia is defined by a percentage of living spermatozoa inferior to 58%, and can be related to male infertility. Several pathological mechanisms may be involved and can be classified either in testicular causes (hyperthyroidism, local hyperthermia, varicocele), or post-testicular causes (epididymal necrospermia, dysregulation of seminal plasma, adult polycystic kidney disease, vasectomy reversal, anti-sperm antibodies) or both (infection, toxic, age, spinal cord injury). The first treatment is to correct the underlying cause, if possible. Repetitive ejaculation has demonstrated to be effective as well. Many drugs would also improve the sperm vitality (antioxidants, non-and-steroidal anti-inflammatory drugs) but there is currently no guideline to recommend their use. With necrospermia, fertilization rates are lower but in vitro fertilization (IVF) with Intracytoplasmic sperm injection (ICSI) improves the chances of conception.

Necrospermia, antisperm antibodies, and vasectomy

OBJECTIVE

To present a case of necrospermia and antisperm antibodies after vasectomy reversal and in which motile sperm, subsequently used in intracytoplasmic sperm injection (ICSI) treatment, was found after testicular sperm retrieval.

DESIGN

Case report and literature review.

SETTING

Reproductive medicine unit based in a women's hospital in the United Kingdom.

PATIENT(S)

A 36-year-old man with secondary infertility who presented with necrospermia and antisperm antibodies after vasectomy reversal.

INTERVENTION(S)

Testicular sperm retrieval and IVF with ICSI.

MAIN OUTCOME MEASURE(S)

Presence of motile sperm in testicular sperm extraction biopsies.

RESULT(S)

Motile sperm found after testicular sperm retrieval successfully fertilized oocytes in an ICSI cycle.

CONCLUSION(S)

It appears difficult to dissociate the presence of antisperm antibodies from the necrospermia in our patient. Testicular sperm retrieval appeared to partially overcome the effect of the antisperm antibodies by retrieving sperm before they reach seminal plasma, where they would be exposed to the antibodies.

Contraceptions masculines non déférentielles : revue de la littérature

OBJECTIVES

To review the state of progress of the various male contraceptive methods (with the exception of deferential methods).

MATERIAL AND METHODS

A review of the literature was performed by using the key words: male/contraception, limiting the search to original articles in English and French. Articles on vasectomy and the other deferential methods of contraception are not considered in the present review.

RESULTS

Three methods of male contraception are widely used at the present time: withdrawal, male condom and vasectomy, although other types of male contraception have been shown to be effective, including hormonal contraception, which appears to be the most promising technique and the subject of the majority of research. Other contraceptive methods (immunological, thermal...) could constitute possible alternatives.

CONCLUSION

Male contraception remains under-used, as only male condoms are commonly used (apart from withdrawal and vasectomy). Consequently, new research protocols in the field of male contraception must be strongly encouraged.

Epididymis-Specific Pathologic Disorders in Rats Exposed to Gossypol from Weaning Through Puberty

Previous work in our laboratory revealed that the pubertal period of reproductive development in the male rat was particularly vulnerable to gossypol exposure, with a higher frequency of round structures in the lumen of the cauda epididymidis in the treated rats. Herein, we utilized hemicastration and electron microscopy to confirm that the epididymis is a definitive target of gossypol. Although exposure to gossypol from weaning through puberty caused a significant decrease in daily sperm production, as well as in the concentration of sperm in the epididymis, serum testosterone levels and reproductive organ weights were not altered. In gossypol treated rats, sperm morphology was compromised severely, but the epithelium in testis and epididymis appeared morphologically normal. Ultrastructural examination revealed that round structures, present only in gossypol exposed males, represented: (1) principal cells exfoliated from the epididymal epithelium; (2) epididymal epithelial cell cytoplasm containing degenerating sperm; and (3) degenerating epithelial cells, consisting of vesicles and particles of different sizes, forms and densities. Taken together, the data confirm that gossypol targets the epididymis, disturbing both the structure and function of this organ, and presumably disrupts sperm maturation.

Gossypol blood levels and inhibition of spermatogenesis in men taking gossypol as a contraceptive. A multicenter, international, dose-finding study

The safety and efficacy of gossypol continues to be controversial. The aim of this study was to evaluate gossypol as a contraceptive pill for men at doses lower than those previously prescribed and in men from various ethnic origin. A total of 151 men from Brazil, Nigeria, Kenya, and China were divided into two groups. Both groups received 15 mg gossypol/day for 12 or 16 weeks to reach spermatogenesis suppression. Subjects were then randomized to either 7.5 or 10 mg/day for 40 weeks. In addition, 51 men were enrolled as a control group. In all, 81 subjects attained spermatogenesis suppression. Only one man discontinued treatment because of tiredness. Potassium levels fluctuated within the normal range. FSH increased consistently. Testicular volume decreased, but after discontinuation, values returned to levels not statistically different from admission. Of 19 subjects on the 7.5 mg/day dose group, 12 recovered sperm counts >20 million/mL within 12 months of discontinuing gossypol. In the 10 mg/day group, sperm counts recovered in only 10 of 24 subjects. Eight of the 43 patients remained azoospermic 1 year after stopping gossypol. All men diagnosed with varicocele failed to reverse spermatogenesis suppression. Gossypol blood levels indicated that sperm suppression occurs independently of concentration, whereas spermatogenesis recovery appears to be concentration-dependent. Gossypol may become a medical alternative to surgical vasectomy when the delay in onset of infertility is acceptable. When taken for 1 year, gossypol causes no reduction in sexual desire or frequency of intercourse. The possibility of reversal, occurring in 51% of the men on this regimen within 1 year after stopping gossypol, is an advantage of this compound as compared with surgical sterilization in many parts of the world.

A nerve growth factor from the venom of Chinese cobra (Naja naja atra) and its effects on male reproductive system in rats

A nerve growth factor (NGF) was isolated from the venom of Chinese cobra (Naja naja atra) by ion exchange chromatography, gel filtration and fast protein liquid chromatography (FPLC). The N-terminal sequence of 22 amino acid residues was identical with other NGFs previously purified from the venom of the same genus. The NGF monomer molecular weight was estimated to be 13,500 by reducing SDS-PAGE and the isoelectric point was determined to be 7.2 by isoelectric focusing electrophoresis. NGF improved the epididymal sperm motility of male rats and increased the pregnancy rate and fetus number of mated female rats. The serum levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) of male rats administrated NGF + gossypol was lower than that of male rats administrated gossypol. Histological sections of testes and epididymides showed that NGF reduced the destructive effects of gossypol on rat testes.

AIDS and reproductive health

Over 24 million adults worldwide have been infected with HIV. Primarily a sexually transmitted disease, AIDS is inexorably linked to reproductive health and care. Because HIV tends to infect those who are in their reproductive years, the impact of this disease on population growth and life expectancy is projected to be immense in some parts of the world, especially in sub-Saharan Africa. Not least is the challenge to individual families and infant care programs to care for AIDS babies. Estimates of the rate of vertical transmission of HIV range from < 10 to 46%. Transmission through sexual contact accounts for 75-85% of HIV infection worldwide, and today, nearly 20 years into the epidemic, the main tool to stall the spread is advocating change in sexual conduct. Numerous studies leave no doubt that the attributable risk of co-infection with other STDs--both ulcerative and non-ulcerative--in heterosexual transmission is substantial. The only known contraceptive method proven to reduce both infectiousness and susceptibility to HIV is barrier contraception. Spermicidal agents currently available have not been shown to reduce HIV concentrations in genital secretions, or to reduce transmission of the virus. The challenges that lie ahead are tremendous: we must continue to focus on development of affordable preventive measures; urge policy-makers to back further research in prevention to complement condom use; and advocate for continued support of basic research to learn more about fundamental mechanisms of HIV transmission.

Influence of gossypol on the secretory function of cultured rat sertoli cells

Cottonseed gossypol is a potent male contraceptive in several mammalian species including man. Sertoli cells play a crucial role in spermatogenesis. Therefore, the antifertility competence of gossypol may reflect a change in Sertoli cell function. Rat primary cultures were used to examine the effect of gossypol on cell viability, mitochondrial dehydrogenase function, lactate production and secretion of the Sertoli cell-specific protein inhibin. Exposure for 24 h to gossypol (3-6 microM) significantly enhance secretion of lactate but reduce secretion of inhibin without affecting cell viability. At 9-15 microM, the observed decrease of both lactate and inhibin accumulation apparently resulted from Sertoli cell degeneration and death, because viability and mitochondrial function were also reduced. The results suggest that mitochondria of Sertoli cells are a possible target for gossypol-induced infertility.

Gossypol: reasons for its failure to be accepted as a safe, reversible male antifertility drug

Following clinical trials conducted in China in the 1970s, gossypol was proposed as a drug for male contraceptive use. This review summarizes the extensive investigations on formal animal toxicology and on the recovery of fertility in men after stopping gossypol treatment which led to the decision by the Special Programme of Research, Development and Research Training in Human Reproduction (HRP) at the World Health Organization (WHO), that gossypol would not be acceptable as an antifertility drug. It is concluded that the assessment of gossypol reinforces the mandatory requirement that future contraceptive drugs must be developed by the established routes of appropriate animal toxicology and phased clinical studies.

Effect of antispermatogenic compound CDRI-84/35 on marker enzymes of rat testis cells. A study on site of action

Marker enzymes of Sertoli and germ cells were estimated to study the mechanism of action of antispermatogenic compound CDRI 84/35 in adult male rat testis. Animals were killed after 22, 41, and 64 days of treatment with antispermatogenic dose of CDRI 84/35 in order to evaluate the effect of the compound on spermatid, spermatocyte, and spermatogonial stages, respectively. Studies were also extended to a recovery period of 90 days. Results indicate a direction action of the compound on germ cells, with no apparent effect on Sertoli cells. Studies also show a massive depletion of postmeiotic germ cells after the treatment, with some damage to premeiotic germ cells as well. Reversibility of the compound was partial, with the marker enzymes of pre- and postmeiotic germ cells not being restored to control levels after withdrawal of treatment.

The effects of cyclic adenosine monophosphate, forskolin, and theophylline on motility parameters in gossypol-treated human sperm

OBJECTIVE

To examine the effect of gossypol on human sperm in vitro and the mechanism for the effect.

DESIGN

Fresh sperm ejaculates obtained from normal donors to the University of Kentucky Andrology Donor Program were exposed to gossypol. Motility was studied manually and using computer-assisted sperm analysis. In subsequent experiments, the effects of forskolin, theophylline, and cyclic adenosine monophosphate (cAMP) on sperm motion were measured.

SETTING

University of Kentucky Department of Obstetrics and Gynecology Andrology Laboratory.

MAIN OUTCOME MEASURES

Manual and computer-assisted measurements of sperm motility and motion characteristics.

RESULTS

Gossypol inhibited sperm motility, which could be reversed partially by increasing cAMP.

CONCLUSION

Gossypol exposure in vitro adversely affects sperm motility in a dose- and time-dependent manner by a cAMP-dependent mechanism.

Genetic toxicity studies of gossypol

Gossypol, a polyphenolic compound extracted from cotton plants, shows promise for use as a male contraceptive, as well as a treatment for gynecological disorders, cancer, and certain microbial diseases. Before gossypol can be considered safe for widespread human use, particularly by healthy people of childbearing age, its effect on normal genetic processes should be understood. Characterization of gossypol's genotoxic potential has not been approached systematically, although numerous clinical and laboratory studies have addressed issues relating to genetic effects of gossypol. This review summarizes results of relevant studies and offers recommendations for the emphasis of future efforts to understand gossypol's genotoxicity potential. Evidence suggesting that gossypol has any genotoxic effects in mammals under normal physiologic conditions so far is weak, at best. However, several unresolved issues that are important for establishing long-term genetic safety of gossypol were uncovered by this analysis. These include the need for a better understanding of the significance of weak increases in SCE frequency seen in a number of laboratory exposure studies, and more definitive, comprehensive animal tumor bioassay data.

The effect of the male contraceptive agent gossypol acetic acid on mouse bone marrow cells in vivo: micronuclei and mitotic index

In this work the genotoxic effect of gossypol acetic acid (gossypol) was evaluated by determining the frequency of micronuclei and mitotic index in male mouse bone marrow cells in vivo. Bone marrow cells were collected at 24th hour after the single intraperitoneal (20, 40, and 80 micrograms/g) administration of gossypol. Polychromatic erythrocytes (PCEs) in the bone marrow were then evaluated with respect to micronuclei frequency. The dose-dependent increase in the micronuclei frequency was observed. However, when compared with the control group, the increase was not found to be significant (P > 0.05). Also the mitotic index values were not found to be different from those control values (P > 0.05). The results suggest that gossypol is not a clastogenic and mutagenic agent in mouse bone marrow cells in vivo.

Zone-specific hepatotoxicity of gossypol in perfused rat liver

Gossypol selectively damages the periportal region of lobules in perfused rat liver, while retrograde perfusion caused pericentral liver damage. Moreover, the addition of 0.4% bovine serum albumin(BSA) to the perfusate completely prevented the toxic effect of gossypol on hepatocytes, decreasing the absorption of gossypol by the liver. This study indicates that the damage caused by gossypol depends upon the direction of exposure and can be protected against by its binding to BSA.

Gossypol pharmacokinetics in mid-lactation Brown Swiss dairy cows

A bolus equivalent to 450 ppm (dosage based on average feed intake for lactating dairy cows of similar mass) of gossypol was administered orally to three Brown Swiss dairy cows in mid lactation daily for a 7-day treatment period. Blood samples were taken during a 2-day pretreatment period, the 7-day treatment period and a 6-day recovery period. The serum recovered from the cows was stored at -20 degrees C until analysis for extractable gossypol content. The highest concentration of gossypol (a mean of 0.53 microgram/ml serum) was attained in all the cows on day 6 of the treatment period, indicating that a steady-state condition had been reached before the end of the treatment period. The gossypol concentrations then gradually declined during the 6-day recovery period but never fell to the zero baseline. The cows exhibited terminal elimination half-lives of 67, 67.5 and 40 h. Gossypol elimination was best described by a bi-exponential decay curve in two cows and a mono-exponential decay curve in the remaining cow.

Effect of gossypol on thyroid hormones in young female rats

The study was designed to examine the effect of gossypol on thyroid function in young female rats. Forty young Sprague-Dawley female rats were randomly assigned to four treatment groups. The dosages of gossypol acetic acid (gossypol) used for this experiment were 1, 5 and 10 mg/kg body weight/day in 0.5 ml potassium phosphate buffer subcutaneously started from day 34 of age for 15 consecutive days. The control group was treated with vehicle alone. Animals were sacrificed 15 days after gossypol treatment. Blood samples and sera were collected and prepared for measurement of thyroid hormones by radioimmunoassay. The levels of free thyroxine (T4), 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine (reverse T3, rT3) in control rats at age 49 days averaged 55.90 +/- 7.7, 670 +/- 90, and 71.7 +/- 5.7 pg/ml of serum, respectively. Fifteen days after gossypol treatment at 5 and 10 mg/kg/day, the free T4 levels significantly decreased to 21.96 +/- 2.1 and 11.12 +/- 1.5 pg/ml of serum, the T3 levels significantly decreased to 430 +/- 89, 359 +/- 90 pg/ml of serum and the rT3 levels were significantly decreased to 37.20 +/- 7.3, and 24.20 +/- 6.0 pg/ml of serum, respectively. However, the serum levels of free T4, T3 and rT3 in the 1 mg/kg/day of gossypol-treated animals were not significantly different from the controls. Five to 15 days after initiation of gossypol treatment, both body weight gain and food intake appeared to be significantly reduced at 5 and 10 mg/kg/day of gossypol treatment. This trend continued to the end of the 15-day gossypol treatment. The results provide new evidence that gossypol might have exerted its antithyroid function by an unknown mechanism that triggered an interference in body metabolism, thus causing the loss of food intake and body weight gain in young female animals.

Inactivation of human immunodeficiency virus in vitro by gossypol

Gossypol, a polyphenolic aldehyde extracted from cottonseed, is a male anti-fertility agent which has been reported to have anti-viral activity. In this paper we report that gossypol inactivates human immunodeficiency virus (HIV) in an in vitro system. Following exposure of cell-free incubates of HIV to 100 uM gossypol, ultracentrifugation and inoculation of the washed pellet onto H9 cells, there is no evidence of elevated reverse transcriptase activity over 21 days. Treatment with lower concentrations of gossypol reduces the peak and lengthens the time to maximal reverse transcriptase activity compared with control cultures. These observations suggest that gossypol could be used as a vaginal spermicidal/virucidal agent. The mechanism of the in vitro anti-viral action as well as the effect of orally administered gossypol on the infectivity of semen of HIV-seropositive men warrant further study.

Effect of gossypol on the thyroid in young rats

The effect of gossypol on thyroid structure and function was examined. Groups of young male rats were subcutaneously injected daily with 0.2 ml gossypol acetic acid in doses of 1, 5, or 10 mg per kg body weight. Control rats were injected with vehicle only. At the end of the 15-day treatment, there was a dose-dependent decrease in the serum concentrations of thyroid hormones, i.e., free thyroxine, triiodothyronine, and reverse triiodothyronine. Histopathological examination revealed focal degeneration of thyroid follicles after a dose of 1 mg gossypol per kg body weight; widespread follicular atrophy occurred with 5 mg and 10 mg gossypol per kg body weight. The degenerating follicles were lined with discontinuous cuboidal or squamous follicular epithelium, some of which exfoliated into colloid.

Primary mitochondrial activity of gossypol in yeast and mammalian cells

Gossypol showed primary antimitochondrial activity in yeast cells in that the drug (1) inhibited growth of cells utilizing mitochondrial substrates as carbon and energy sources, and (2) selectively inhibited mitochondrial protein synthesis. Primary antimitochondrial activity was demonstrated in guinea-pig keratinocytes (GPK) by early arrest of growth and loss of viability in medium with glutamine (a mitochondrial substrate) as carbon and energy source compared with cells utilizing glucose. Gossypol depressed oxygen uptake directly in respiring cells. Gossypol interacted with the known antimitochondrial agents ethidium bromide and 5-fluorouracil (FU), potentiating the activity of FU but reversing that of ethidium bromide in yeast and GPK. Also, the activity of the mitochondrial inhibitor oligomycin was reversed by the presence of gossypol in yeast cells but not tested in GPK. The uptake and retention of the mitochondria-specific dye rhodamine 123 were much depressed by gossypol in GPK. Gossypol showed little or no inhibitory effects in yeast or GPK in the presence of ethanol (0.2-0.5%). The drug was not mutagenic with respect to the yeast mitochondrial system. It was tentatively suggested that mitochondrial perturbation could explain the antifertility effect of gossypol if it is assumed that mitochondria have a special role to play in spermatogenesis and sperm motility, making these tissues more sensitive to mitochondrial inhibitors than somatic cells.

Failed fertilization during an in vitro fertilization cycle after oral ingestion of amantadine hydrochloride

Oocyte fertilization occurred during three in vitro fertilization/embryo transfer (IVF/ET) treatment cycles of an infertile couple but failed during an IVF cycle when the husband took amantadine for prophylaxis against viral infection. Semen parameters were similar to those of other cycles attempted by this couple as well as to those of other IVF couples treated concurrently. We circumstantially suggest that amantadine, and potentially other ingestible medications or foods, while not spermicidal, may impair gamete function during IVF/ET.

Variable sister-chromatid exchange response in human lymphocytes exposed in vitro to gossypol acetic acid

Gossypol has potential for widespread use as a male oral antifertility agent in humans since it appears to be highly efficacious, with reversible spermatostatic effects and minimal side effects. Furthermore, it is both inexpensive and readily available. Therefore, a thorough understanding of gossypol's genotoxic potential is critical. Although genotoxicity studies have produced conflicting reports, increased sister-chromatid exchange (SCE) and DNA-strand breaks have been reported in human cells exposed to gossypol in vitro. In the present study, SCE was examined in purified human lymphocytes and whole blood cultures exposed to gossypol acetic acid at various concentrations in serum-free medium. A small but statistically significant increase in SCE was observed in pooled analysis of 7 donors in whole blood cultures exposed to 0.70 microM gossypol acetic acid (p less than 0.02). Individual analyses revealed only one donor with a significant SCE response (p less than 0.001). In subsequent experiments, exposure at higher doses had no effect on SCE frequencies. A small but significant increase in SCE was observed in ficoll/hypaque purified lymphocytes exposed to 0.07 and 0.70 microM gossypol acetic acid. Interpretation of SCE data with variable response is discussed.

Ultrastructure of the testis and epididymis of Japanese quail (Coturnix coturnix japonica) administered gossypol

When Japanese quail were given gossypol acetic acid intramuscularly at 25 mg/kg body weight per day for 9 days, testis/body weights were reduced to 63% of those of controls. Lumina of the seminiferous tubules became smaller but were packed with tails of spermatids. Mitochondria of spermatids changed in shape from elongated to round. After administration of gossypol for 21 days, testis/body weights were 14% of those of controls. Lumina of seminiferous tubules were completely collapsed, germinal epithelia became much thinner, and basal lamina of the germinal epithelium underwent extensive ruffling. Although primary spermatocytes were seen, neither spermatids nor sperm were present. The cytoplasm of germinal epithelial cells was packed with numerous lipid droplets. At Day 8 of withdrawal following 21 days of gossypol administration, testis/body weights were 23% of those of controls. Reduced numbers of lipid inclusions and partial recovery of spermatogenesis in the testis were observed. In the epididymal region, epithelial cells of the ductuli efferentes progressively accumulated lipid droplets, and luminal collapse was seen after 21 days of gossypol administration. After gossypol administration for 21 days, no sperm were found in the ductus epididymidis, the lumina were collapsed, and microvilli of the epithelial cells were lost. At Day 8 of withdrawal after 21 days of gossypol administration, lipid content was reduced in the ductuli efferentes. The lumina of the ductus epididymidis were open, but no spermatozoa were seen. These observations indicate that gossypol severely altered tissues of the quail testis and epididymal region. However, this alteration seems to be reversible.

Recovery of sperm production following the cessation of gossypol treatment: a two-centre study in China

A number of variables were investigated in 46 men who had stopped taking gossypol for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) of the men were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 X 10(6)/ml and 30.7 X 10(6), respectively. Twenty-eight men (61%) recovered to a defined threshold of spermatogenic function (sperm concentration greater than or equal to 20 X 10(6)/ml), with a median recovery time of 1.1 years. However, 18 men (39%) had not recovered to this degree of spermatogenic function after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The influence of individual baseline variables on the time to defined recovery was examined using Kaplan-Meier curves for groups and their joint effect by Cox's regression model. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.

Clinical experience with gossypol in non-Chinese men: a follow-up

Gossypol monoacetic acid was administered to 12 Brazilian volunteers. The initial dose was 20 mg daily for 4 months. The dose was then reduced to 60 mg weekly (20 mg three times weekly). A significant reduction in sperm motility was detected in all subjects. An increase in the number of immature cells in the ejaculate was also detected in all subjects. Severe oligospermia or azoospermia developed in all subjects at the end of the loading phase. Two years following discontinuation, 3 men were still azoospermic. Only 1 man who was azoospermic 2 years after discontinuation had a late (3 years) recovery. Two of the 3 men who were subjected to high spermatic vein ligation because of varicocele remained azoospermic 2 years after the operation. The third patient, who did not have the operation, also remained azoospermic. Of the 9 patients who recovered, 3 had fathered children during the last 2 years.

Cytogenetic effects of vaginally administered gossypol in murine bone marrow cells

The cytogenetic effects of gossypol were evaluated by determining the frequency of sister chromatid exchanges (SCEs), percentage of pulverized metaphases, mitotic indices and micronuclei in bone marrow cells of mice treated per vaginam. A dose-dependent increase in the frequency of SCEs was observed when gossypol suspended in corn oil was administered at dosages of 10, 20 or 40 micrograms/g. In comparison with controls, incidences of SCEs were significantly higher in mice given 20 and 40 micrograms/g gossypol, whereas the mitotic indices, percentages of pulverized metaphases and the frequency of interphase micronuclei in treated animals were not different from their control counterparts. The SCE data suggest that gossypol has a DNA-damaging potency in murine bone marrow cells.

Clinical trial of gossypol as a male contraceptive drug. Part II. Hypokalemia study

A randomized controlled study was designed to evaluate the merit of whether ingesting potassium salt or potassium (K) blocking agent while using gossypol contraceptive drug could alleviate the symptom of hypokalemia. Results indicate that K salt supplementation did not reverse the gossypol-related hypokalemia and that the blocking agent triamterene did not prevent loss of or enhance the retention of serum K.

Quantitative analysis of germ cells and Leydig cells in rat made infertile with gossypol

This study utilized improved methods of fixation and plastic embedding to quantitatively evaluate the effects of gossypol on germ cells and Leydig cells in testes of rats made infertile with gossypol. Rats were fed by gavage with 10, 20 or 30 mg/kg per day of gossypol for 9 weeks; control animals received the vehicle alone. Numbers of A spermatogonia, preleptotene and pachytene spermatocytes, and step 7 or 8 spermatids per Sertoli cell were counted in stages VII-VIII of the cycle of the seminiferous epithelium. Although high doses (30 mg/kg) of gossypol produced a significant decrease in the relative number of germ cells compared with vehicle-treated controls, no significant deviation in the relative number of germ cells was noted between controls and rats made infertile with 10 or 20 mg/kg/day of gossypol. Stereologic techniques were used to assess the changes in the Leydig cells. No significant deviation in the Leydig cell morphology, cell number, or cell volume was noted as a result of gossypol treatment at the dose levels employed. It appears that germ cell depletion, such as that caused by high doses of gossypol, is not mediated by a change in Leydig cell function. The present report emphasizes the importance of studies to determine the minimal effective doses for gossypol's antifertility activity in animal models as well as in man.

Kinetic characterization of the inhibition of purified cynomolgus monkey lactate dehydrogenase isozymes by gossypol

This report describes the results of the first step in a sequence of experiments designed to test the hypothesis that the sperm-specific isozyme of lactate dehydrogenase (LDH-C4), is a site of action of the potential male contraceptive agent gossypol. Cynomolgus monkey LDH-A4, LDH-B4 and LDH-C4 were purified and kinetically characterized. LDH-A4 and LDH-B4 exhibited "linear mixed-type" inhibition by gossypol with both lactate and pyruvate as variable substrates. LDH-C4 also exhibited "linear mixed-type" inhibition with lactate as substrate. However, the C4 isozyme exhibited "parabolic mixed-type" inhibition by gossypol and substrate inhibition with pyruvate as substrate, the latter due to abortive complex formation. Of the three isozymes, LDH-C4 exhibited the lowest apparent Km for pyruvate and the highest apparent Km for lactate. The LDH-C4 form was found to be the most sensitive isozyme to gossypol inhibition, since it had the lowest apparent Ki values for gossypol inhibition. The effect of gossypol on coenzyme binding to LDH-C4 was examined and gossypol binding was found to inhibit binding and release of NADH but not NAD+, an effect possibly due to its interaction with the more hydrophobic loop region of LDH-C4.

Membrane structural/functional perturbations induced by gossypol. Effects on membrane order, liposome permeability, and insulin-sensitive hexose transport

The effects of gossypol on membrane structure and membrane-associated functions were studied to explore possible reasons for the ability of gossypol to disrupt cellular processes, many of which involve intracellular and plasma membranes. The experiments reported here measured the effects of gossypol on membrane order, permeability, and hexose transport. Electron spin resonance (ESR) studies of I(12,3) nitroxide fatty acid spin-labeled unilamellar liposomes showed that exposure to 0.05 to 4 mM gossypol caused a dose-dependent increase in the polarity-corrected order parameter (S), indicating reduced motional freedom of the spin probe after exposure to gossypol. This observation is consistent with the idea that gossypol causes an ordering or "condensing" of the membrane lipid matrix. Gossypol-induced changes in order parameter in phosphatidylcholine:cholesterol liposomes varied depending on the liposome composition. Liposomes exposed to gossypol also showed increasing permeability to glycerol as the gossypol:phospholipid ratio increased up to 10 mole %. Higher concentrations of gossypol were less effective at enhancing permeability. In addition, basal and insulin-stimulated 2-deoxy-D-[3H]glucose transport were inhibited in freshly isolated rat adipocytes incubated with gossypol at 37 degrees. Half-maximal inhibition occurred at approximately 0.2 mM for uptake in both the presence and absence of 40 ng/ml insulin. Microscopic observation of the cells under low power (40 X) confirmed that diminished hexose transport was not simply due to breakage of the adipocyte plasma membrane, resulting in a decrease in intact cell population and decreased accumulation of label in the gossypol-treated cells. Gossypol produced no significant changes in numbers of intact cells or gross morphology at the concentrations tested. We suggest that ordering and increased permeability of the lipid regions of plasma and subcellular membranes may contribute to some of the toxic and pharmacologic properties of gossypol. Our results also support the idea that gossypol may exert more pronounced effects in cells that are most sensitive to variations in availability of glucose substrates for energy metabolism.

Studies on structure-activity relationship of gossypol, gossypol ethers and three naphthaldehydes in the inhibition of spermatozoal metabolism

Gossypol tetramethyl ether [C30 H24 O2(OCH3)4] and gossypol hexamethyl ether [C30 H24 O2(OCH3)6], which in contrast to gossypol are stable compounds, were tested for their ability to depress fructose degradation in fresh human sperm cells. Both ethers inhibited spermatozoal fructolysis, yet less effectively than did the parent compound. A synthetic compound, O-hydroxylnaphthaldehyde, and two commercially available preparations, 1- and 2-naphthaldehydes, were also tested under the same experimental conditions. These preparations represent about half of the gossypol molecule and possess a reactive aldehyde group in their molecules. Their inhibitory effect on fructose degradation in fresh human sperm cells, however, was considerably smaller than that of gossypol itself. It thus appears that the whole ring structure of gossypol rather than the intact aldehyde group is required for an effective inhibition of spermatozoal energy metabolism.

Induction of sister chromatid exchanges and chromosome damage by gossypol in bone marrow cells of mice

The chromosome-damaging potential of gossypol was evaluated by scoring sister chromatid exchanges (SCEs), determining the percentage of pulverized metaphases and the mitotic index in bone marrow cells of mice. Bone marrow cells were collected approximately 21 hours after the intraperitoneal (0,20,40,80, or 160 micrograms/g) and oral (0,40,80, or 160 micrograms/g) administration of gossypol acetic acid. Irrespective of the dosing schedule (single or multiple doses), the vehicle used (physiological saline, corn oil, or 10% aqueous ethanol), and the route of administration, the mean SCE count per cell was significantly higher (P less than 0.05) in gossypol-treated groups than their control counterparts. At 80 and 160 micrograms/g dose levels, the occurrence of metaphase chromosome pulverization was significantly greater, while mitotic index values were markedly lower than those of the corresponding control values. The results suggest that gossypol is a potentially mutagenic and clastogenic agent in murine bone marrow cells.

The in vivo effect of gossypol on macromolecular synthesis in rat testis

An in vitro study showed that in rat testis gossypol acts as a nonspecific inhibitor of macromolecular synthesis. In this report we describe the in vivo effect of gossypol on DNA, RNA, and protein synthesis in rat testis. Gossypol treatment of rats (20 mg/kg) for 6, 10 and 16 weeks resulted in partial inhibition of macromolecular synthesis. When status of infertility is achieved after 6 weeks, macromolecular synthesis of the spermatogenetic epithelium is not essentially affected by gossypol. In contrast to the previously described DNA strand breaking induction of gossypol in human fibroblasts in vitro, no DNA strand breaking in testes of gossypol-treated rats was found as established by alkaline sucrose gradient centrifugation.

Antifertility effect of polyvinylpyrrolidone-gossypol and gossypol in male rats

Thirty-nine adult male Wistar rats were administered 20 mg/kg or 24.3 mg/kg polyvinylpyrrolidone-gossypol (PVP-G) and 20 mg/kg gossypol acetic acid (G-A) 6 times a week for 6 weeks. Mating test was taken to evaluate the antifertility effect. Caudal sperm count, body weight, sex and accessory sex organ weights were recorded. At the end of 6 weeks treatment, the recovery period of 6 weeks was investigated. The results showed that the onset of antifertility action and recovery with PVP-G are faster than with G-A.

Gossypol and hypokalaemia

One major side effect of administration of gossypol as a male fertility regulating agent is the occurrence of hypokalaemic paralysis. We have reviewed the common causes of hypokalaemia in clinical practice and previous studies of gossypol-induced hypokalaemia in animals and man. The available evidences suggest that gossypol induced renal leakage of potassium. The most likely mechanism is a direct toxic effect of gossypol on the renal tubules.

Reversible changes in rat spermatogenesis induced by an antifertility substance (Gossypol). A histochemical report

Male rats received Gossypol 30 mg/kg body mass daily through intubation for 30 and 60 d. The testes were processed for histological and histochemical lipid staining, thiamine pyrophosphatase (TPPase), and alpha-glycerophosphate dehydrogenase (alpha-GPDH)--examinations. Gossypol induced effects were: various types of deformations of elongated spermatids, and their loss of orientation towards the lamina propria during the maturation phase; displacement of germ cells and occasionally also of Sertoli cells towards the lumen of the seminiferous tubule in form of a "puff". TPPase was observed in the supranuclear region of dislocated round spermatids and pachytene spermatocytes. alpha-GPDH was observed in the split pieces of mid- and tail pieces of elongated spermatids enclosed in the "puff". The induced effects were reversible.

Recovery of normal testicular ultrastructure and sperm motility after cessation of gossypol treatment in rats

This study evaluates the reversibility of the effects of gossypol on testicular ultrastructure and the motility of epididymal spermatozoa. Adult male rats were treated 6 days weekly with the vehicle alone (Group A), or with 10 (Group B) or 20 (Group C) mg/kg of gossypol for 12 weeks, and then sacrificed six or 12 weeks after cessation of treatment. Although epididymal spermatozoa in Groups B and C were 100% immotile after gossypol treatment, little evidence of abnormality could be detected with the light microscope in the seminiferous tubules or interstitium. By contrast, at the ultrastructural level, there were demonstrable pathognomonic defects in the mitochondrial sheath and axonemes of step 18 and 19 spermatids which were identical to those reported earlier (Hoffer, 1983). In addition, an ultrastructural defect in the flagella of late testicular spermatozoa is described for the first time. This defect consists of an indentation, or constriction, of the mitochondrial sheath at outer dense fibers (ODFs) 1, 2, and 9, resulting in a separation of these 3 ODFs from the other fibers. This defect, though visible in an earlier ultrastructural study (Hoffer, 1983), was not described. In Group B rats allowed to recover from gossypol treatment, ultrastructural defects in step 18 and 19 spermatids could not be detected at six or at 12 weeks after cessation of treatment, and sperm motility also did not differ significantly from controls by the end of either recovery period. In Group C rats, sperm motility returned to the normal range within six weeks after treatment ended, but a few morphological defects in the midpiece and axoneme of late spermatids could still be detected with the electron microscope.(ABSTRACT TRUNCATED AT 250 WORDS)