51
|
Brant WO, Myers JB, Carrell DT, Smith JF. Male athletic activities and their effects on semen and hormonal parameters. PHYSICIAN SPORTSMED 2010; 38:114-20. [PMID: 20959704 DOI: 10.3810/psm.2010.10.1816] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Infertility is generally defined as the inability to conceive a pregnancy or the failure to do so within a reasonable period (typically 12 months). Approximately 85% of couples conceive a first pregnancy within 12 months. The prevalence of infertility has increased over the past 10 years, with approximately 10 million affected couples in the United States. Roughly 40% to 50% of infertility is either due to, or is contributed by, a male factor. Given how common the condition is, men and their partners are understandably concerned and interested in identifying and eliminating risk factors for male infertility. This article reviews the available literature on various aspects of male infertility related to athletic pursuits. These include the effects of exercise on semen parameters, hormonal axes, and testicular health. Due to the prevalence and particular relevance of anabolic steroid use by athletes and the impact of steroid use on fertility, this topic is also reviewed.
Collapse
Affiliation(s)
- William O Brant
- Department of Surgery (Urology), Salt Lake City, UT 84132, USA.
| | | | | | | |
Collapse
|
52
|
Eberhardt J, van Wersch A, Meikle N. Attitudes towards the male contraceptive pill in men and women in casual and stable sexual relationships. ACTA ACUST UNITED AC 2010; 35:161-5. [PMID: 19622206 DOI: 10.1783/147118909788707986] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND METHODOLOGY Men's and women's attitudes towards the male contraceptive pill and their trust in the effective use of the male pill were investigated, as well as the associated variables of reported health behaviours, perceived self-efficacy and type of sexual relationship, using a questionnaire survey. RESULTS Although both sexes had a favourable attitude towards the male pill, females had a more positive attitude than men. Conversely, women had less trust that men would use the male pill effectively. Males in stable sexual relationships were more positive about the male pill than those in casual sexual relationships. Gender, relationship type and trust in the effective use of the male pill reliably predicted attitude towards the male pill. High perceived self-efficacy was related to engaging in more health behaviours, and in men a positive association between health behaviours and attitude towards the male pill has been found. DISCUSSION AND CONCLUSIONS A positive attitude towards the male pill does not automatically imply that the individual is confident about its effective use. Once the male pill is widely available, promotional campaigns could target not only men but also their female partners, as the latter tend to come into contact with health services more frequently. In order to increase confidence in effective implementation, a variety of presentations of the male pill should be made available in line with individual needs and lifestyles.
Collapse
Affiliation(s)
- Judith Eberhardt
- School of Social Sciences and Law, University of Teesside, Middlesbrough, UK
| | | | | |
Collapse
|
53
|
Sharpe RM. Environmental/lifestyle effects on spermatogenesis. Philos Trans R Soc Lond B Biol Sci 2010; 365:1697-712. [PMID: 20403879 DOI: 10.1098/rstb.2009.0206] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The high incidence of low sperm counts in young (European) men and evidence for declining sperm counts in recent decades mean that the environmental/lifestyle impact on spermatogenesis is an important health issue. This review assesses potential causes involving adverse effects on testis development in perinatal life (primarily effects on Sertoli cell number), which are probably irreversible, or effects on the process of spermatogenesis in adulthood, which are probably mainly reversible. Several lifestyle-related (obesity, smoking) and environmental (exposure to traffic exhaust fumes, dioxins, combustion products) factors appear to negatively affect both the perinatal and adult testes, emphasizing the importance of environmental/lifestyle impacts throughout the life course. Apart from this, public concern about adverse effects of environmental chemicals (ECs) (pesticides, food additives, persistent pollutants such as DDT, polychlorinated biphenyls) on spermatogenesis in adult men are, in general, not supported by the available data for humans. Where adverse effects of ECs have been shown, they are usually in an occupational setting rather than applying to the general population. In contrast, a modern Western lifestyle (sedentary work/lifestyle, obesity) is potentially damaging to sperm production. Spermatogenesis in normal men is poorly organized and inefficient so that men are poorly placed to cope with environmental/lifestyle insults.
Collapse
Affiliation(s)
- Richard M Sharpe
- MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
| |
Collapse
|
54
|
Cheng CY, Mruk DD. New frontiers in nonhormonal male contraception. Contraception 2010; 82:476-82. [PMID: 20933122 DOI: 10.1016/j.contraception.2010.03.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 03/23/2010] [Indexed: 12/11/2022]
Abstract
The world's population is nearing 6.8 billion, and we are in need of a male contraceptive that is safe, effective, reversible and affordable. Hormonal approaches, which employ different formulations of testosterone administered in combination with other hormones, have shown considerable promise in clinical trials, and they are currently at the forefront of research and development. However, the long-term effects of using hormones throughout a male's reproductive life for contraception are unknown, and it may take decades before this information becomes available. Because of this, many investigators are aiming to bring a nonhormonal male contraceptive to the consumer market. Indeed, there are several distinct but feasible avenues in which fertility can be regulated without affecting the hypothalamus-pituitary-testis axis. In this review, we discuss several approaches for fertility control involving the testis that one day may lead to the development of a nonhormonal male contraceptive.
Collapse
Affiliation(s)
- C Yan Cheng
- Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA.
| | | |
Collapse
|
55
|
[Hormonal contraception for men: still a current issue]. Urologe A 2010; 49:16-9. [PMID: 20057989 DOI: 10.1007/s00120-009-2193-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The current status of hormonal contraception in men involves the principle of suppression of gonadotropins, LH, and FSH. This must be achieved as completely as possible to facilitate cessation of spermatogenesis and, thus, reach azoospermia. Simultaneously testosterone has to be replaced. Exogenous testosterone administration achieves the goal of gonadotropin suppression, but needs in addition the supplementation of a gestagen to fully suppress secretion of LH and FSH. Suppression of gonadotropins by steroids requires constant serum concentrations of sex steroids; hence, attempts using daily oral or transdermal preparations were, so far, unsuccessful. Thus, the immediate prospect for male contraception is not a"pill" itself but a regimen of combined injectable steroids, which are in advanced clinical testing.
Collapse
|
56
|
|
57
|
Abstract
This review attempts to give a synopsis of the major aspects concerning the biochemistry of endogenous androgens, supplemented with several facets of physiology, particularly with respect to testosterone. Testosterone continues to be the most common adverse finding declared by World Anti-Doping Agency accredited laboratories, such samples having an augmented testosterone to epitestosterone ratio. Knowledge regarding the precursors and metabolism of endogenous testosterone is therefore fundamental to understanding many of the issues concerning doping with testosterone and its prohormones, including the detection of their administration. Further, adverse findings for nandrolone are frequent, but this steroid and 19-norandrostenedione are also produced endogenously, an appealing hypothesis being that they are minor by-products of the aromatization of androgens. At sports tribunals pertaining to adverse analytical findings of natural androgen administration, experts often raise issues that concern some aspect of steroid biochemistry and physiology. Salient topics included within this review are the origins and interconversion of endogenous androgens, the biosynthesis of testosterone and epitestosterone, the mechanism of aromatization, the molecular biology of the androgen receptor, the hypothalamic-pituitary-testicular axis, disturbances to this axis by anabolic steroid administration, the transport (binding) of androgens in blood, and briefly the metabolism and excretion of androgens.
Collapse
|
58
|
Shahiwala A, Misra A. Preliminary investigation of the nasal delivery of liposomal leuprorelin acetate for contraception in rats. J Pharm Pharmacol 2010; 58:19-26. [PMID: 16393460 DOI: 10.1211/jpp.58.1.0003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The purpose of the study was to investigate the nasal route as a non-invasive alternative for delivery of leuprorelin acetate (leuprolide acetate, LEU) and to achieve an effective concentration of leuprorelin acetate in blood after nasal administration for contraception in rats. The plain drug solution, physical mixture (plain drug along with constituents of liposomes), or drug encapsulated in either neutral or charged liposomes containing 5 μg leuprorelin acetate were administered to rats through the nasal route. The plain drug solution was administered subcutaneously (s.c.). Simultaneous evaluation was performed on the influence of a mucoadhesive agent (chitosan) on nasal absorption of the plain drug and the liposome-encapsulated drug. Blood samples were taken at regular time intervals and subjected to luteinising hormone (LH) analysis using a specific immunoassay kit. The plasma luteinising hormone concentration vs time data of nasal and subcutaneous treatments were plotted and compared with that of subcutaneous administration. Relative percentage of bioavailability (F) for nasal treatments was calculated from plasma concentration vs time plots. Sperm count and fertility performance studies were carried out for selected formulations in rats. Neutral liposomes (LLEU) and negatively-charged liposomes (LLEUn) showed higher relative percentage of bioavailability (F 27.83 and 21.30%, respectively) as compared with the plain drug and the physical mixture (F 10.89 and 10.96%, respectively) after nasal administration. Hence, work on neutral liposomes was continued. F was further improved after incorporation of chitosan i.e. 10.89 to 49.13% for plain leuprorelin acetate and 27.83 to 88.90% for liposomal leuprorelin acetate formulations. Liposomal chitosan formulation administered nasally and leuprorelin acetate solution subcutaneously achieved complete azoospermia. No implantation sites were observed after the mating of female rats with treated males. It was observed that in the treated female rats, the estrous cycles ceased with the same formulations from the first treatment cycle. The findings of these investigations demonstrated that the bioavailability of the nasally-administered liposomal leuprorelin acetate with chitosan formulation was comparable with that of the subcutaneously administered drug. Complete contraception was obtained in male and female rats that had been treated with either the nasally administered liposomal leuprorelin acetate with chitosan or the subcutaneously administered drug.
Collapse
Affiliation(s)
- Aliasgar Shahiwala
- Pharmacy Department, Faculty of Technology & Engineering, Kalabhavan, M. S. University of Baroda, Vadodara-390 001, Gujarat, India
| | | |
Collapse
|
59
|
Huhtaniemi I. A Hormonal Contraceptive for Men: How Close are We? PROGRESS IN BRAIN RESEARCH 2010; 181:273-88. [DOI: 10.1016/s0079-6123(08)81015-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
60
|
Gunenc Z, Bingol B, Gedikbasi A, Yesildaglar N, Erkaya S. Opinions concerning male and female sterilisation in Turkey. EUR J CONTRACEP REPR 2009; 14:375-8. [PMID: 19916765 DOI: 10.3109/13625180903206389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Vasectomy is well accepted in some countries, but uncommonly used in others. The failure of family planning programmes may be the result of men failing to play a role in contraception. This study was carried out to determine the attitudes of women and men regarding male and female sterilisation. STUDY DESIGN Women of reproductive age (17-35 years old; n = 1211) and their husbands (n = 1174) were enrolled in this study. Information was collected from the participants via face-to-face interviews using a questionnaire. RESULTS In our study, 61.4% of women would agree to their husbands' undergoing a vasectomy but only 3.7% of husbands agreed to it. Most (92.7%) men said they would agree to their wives' undergoing a sterilisation and 83.1% of women would agree to tubal occlusion. Only 2% knew anyone who had been sterilised. Nearly a fifth of women thought vasectomy could lead to impotence. CONCLUSION The prejudices against vasectomy are probably due to misinformation. Female sterilisation, however, is widely accepted by both participants. Family planning programmes organised equally for women and men, supported also by mass media could improve access to convenient and effective contraception.
Collapse
Affiliation(s)
- Ziya Gunenc
- Istanbul Maltepe University, Department of Obstetrics and Gynaecology, Istanbul
| | | | | | | | | |
Collapse
|
61
|
Lee NPY, Wong EWP, Mruk DD, Cheng CY. Testicular cell junction: a novel target for male contraception. Curr Med Chem 2009; 16:906-15. [PMID: 19275601 DOI: 10.2174/092986709787549262] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Even though various contraceptive methods are widely available, the number of unwanted pregnancies is still on the rise in developing countries, pressurizing the already resource limited nations. One of the major underlying reasons is the lack of effective, low cost, and safe contraceptives for couples. During the past decade, some studies were performed using animal models to decipher if the Sertoli-germ cell junction in the testis is a target for male fertility regulation. Some of these study models were based on the use of hormones and/or chemicals to disrupt the hypothalamic-pituitary-testicular axis (e.g., androgen-based implants or pills) and others utilized a panel of chemical entities or synthetic peptides to perturb spermatogenesis either reversibly or non-reversibly. Among them, adjudin, a potential male contraceptive, is one of the compounds exerting its action on the unique adherens junctions, known as ectoplasmic specializations, in the testis. Since the testis is equipped with inter-connected cell junctions, an initial targeting of one junction type may affect the others and these accumulative effects could lead to spermatogenic arrest. This review attempts to cover an innovative theme on how male infertility can be achieved by inducing junction instability and defects in the testis, opening a new window of research for male contraceptive development. While it will still take much time and effort of intensive investigation before a product can reach the consumable market, these findings have provided hope for better family planning involving men.
Collapse
Affiliation(s)
- Nikki P Y Lee
- Center for Biomedical Research, Population Council, New York, New York 10065, USA.
| | | | | | | |
Collapse
|
62
|
|
63
|
Jones A, Chen J, Hwang DJ, Miller DD, Dalton JT. Preclinical characterization of a (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro, 4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide: a selective androgen receptor modulator for hormonal male contraception. Endocrinology 2009; 150:385-95. [PMID: 18772237 PMCID: PMC2630904 DOI: 10.1210/en.2008-0674] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The pharmacologic effects of (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro, 4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide (S-23) were characterized in male rats as an animal model of hormonal male contraception. S-23 showed high binding affinity (inhibitory constant = 1.7 +/- 0.2 nm) and was identified as a full agonist in vitro. In castrated male rats, the ED50 of S-23 in the prostate and levator ani muscle was 0.43 and 0.079 mg/d, respectively. In intact male rats treated for 14 d, S-23 alone suppressed LH levels by greater than 50% at doses greater than 0.1 mg/d, with corresponding decreases in the size of the prostate but increases in the size of levator ani muscle. In intact male rats treated for up to 10 wk with S-23 and estradiol benzoate (EB; necessary to maintain sexual behavior in rats), S-23 showed biphasic effects on androgenic tissues and spermatogenesis by suppressing serum concentrations of LH and FSH. EB alone showed no effect on spermatogenesis. In the EB + S-23 (0.1 mg/d) group, four of six animals showed no sperm in the testis and zero pregnancies (none of six) in mating trials. After termination of treatment, infertility was fully reversible, with a 100% pregnancy rate observed after 100 d of recovery. S-23 increased bone mineral density and lean mass but reduced fat mass in a dose-dependent manner. This is the first study to show that a selective androgen receptor modulator combined with EB is an effective and reversible regimen for hormonal male contraception in rats. The beneficial effects of S-23 on the muscle, tissue selectivity, and favorable pharmacokinetic properties make it a strong candidate for use in oral male contraception.
Collapse
Affiliation(s)
- Amanda Jones
- Division of Pharmaceutics, College of Pharmacy, The Ohio State University, 500 West 12th Avenue, L. M. Parks Hall, Room 242, Columbus, Ohio 43210, USA
| | | | | | | | | |
Collapse
|
64
|
Li X, Liu Q, Liu S, Zhang X, Liu Y, Zhang Y. The spatiotemporal expression changes of 16 epididymis-specific genes induced by testosterone, heat, and combination treatment in cynomolgus monkey. Acta Biochim Biophys Sin (Shanghai) 2008. [DOI: 10.1111/j.1745-7270.2008.00451.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
65
|
Abstract
Despite significant advances in contraceptive options for women over the last 50 yr, world population continues to grow rapidly. Scientists and activists alike point to the devastating environmental impacts that population pressures have caused, including global warming from the developed world and hunger and disease in less developed areas. Moreover, almost half of all pregnancies are still unwanted or unplanned. Clearly, there is a need for expanded, reversible, contraceptive options. Multicultural surveys demonstrate the willingness of men to participate in contraception and their female partners to trust them to do so. Notwithstanding their paucity of options, male methods including vasectomy and condoms account for almost one third of contraceptive use in the United States and other countries. Recent international clinical research efforts have demonstrated high efficacy rates (90-95%) for hormonally based male contraceptives. Current barriers to expanded use include limited delivery methods and perceived regulatory obstacles, which stymie introduction to the marketplace. However, advances in oral and injectable androgen delivery are cause for optimism that these hurdles may be overcome. Nonhormonal methods, such as compounds that target sperm motility, are attractive in their theoretical promise of specificity for the reproductive tract. Gene and protein array technologies continue to identify potential targets for this approach. Such nonhormonal agents will likely reach clinical trials in the near future. Great strides have been made in understanding male reproductive physiology; the combined efforts of scientists, clinicians, industry and governmental funding agencies could make an effective, reversible, male contraceptive an option for family planning over the next decade.
Collapse
Affiliation(s)
- Stephanie T Page
- Center for Research in Reproduction and Contraception, Department of Medicine, University of Washington School of Medicine, Seattle, Washington 98195, USA.
| | | | | |
Collapse
|
66
|
Mruk DD, Silvestrini B, Cheng CY. Anchoring junctions as drug targets: role in contraceptive development. Pharmacol Rev 2008; 60:146-80. [PMID: 18483144 DOI: 10.1124/pr.107.07105] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In multicellular organisms, cell-cell interactions are mediated in part by cell junctions, which underlie tissue architecture. Throughout spermatogenesis, for instance, preleptotene leptotene spermatocytes residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier to enter the adluminal compartment for continued development. At the same time, germ cells must also remain attached to Sertoli cells, and numerous studies have reported extensive restructuring at the Sertoli-Sertoli and Sertoli-germ cell interface during germ cell movement across the seminiferous epithelium. Furthermore, the proteins and signaling cascades that regulate adhesion between testicular cells have been largely delineated. These findings have unveiled a number of potential "druggable" targets that can be used to induce premature release of germ cells from the seminiferous epithelium, resulting in transient infertility. Herein, we discuss a novel approach with the aim of developing a nonhormonal male contraceptive for future human use, one that involves perturbing adhesion between Sertoli and germ cells in the testis.
Collapse
Affiliation(s)
- Dolores D Mruk
- Population Council, Center for Biomedical Research, The Mary M Wohlford Laboratory for Male Contraceptive Research, 1230 York Avenue, New York, NY 10065, USA.
| | | | | |
Collapse
|
67
|
Liu PY, Swerdloff RS, Anawalt BD, Anderson RA, Bremner WJ, Elliesen J, Gu YQ, Kersemaekers WM, McLachlan RI, Meriggiola MC, Nieschlag E, Sitruk-Ware R, Vogelsong K, Wang XH, Wu FCW, Zitzmann M, Handelsman DJ, Wang C. Determinants of the rate and extent of spermatogenic suppression during hormonal male contraception: an integrated analysis. J Clin Endocrinol Metab 2008; 93:1774-83. [PMID: 18303073 PMCID: PMC5393365 DOI: 10.1210/jc.2007-2768] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Accepted: 02/20/2008] [Indexed: 11/19/2022]
Abstract
CONTEXT Male hormonal contraceptive methods require effective suppression of sperm output. OBJECTIVE The objective of the study was to define the covariables that influence the rate and extent of suppression of spermatogenesis to a level shown in previous World Health Organization-sponsored studies to be sufficient for contraceptive purposes (< or =1 million/ml). DESIGN This was an integrated analysis of all published male hormonal contraceptive studies of at least 3 months' treatment duration. SETTING Deidentified individual subject data were provided by investigators of 30 studies published between 1990 and 2006. PARTICIPANTS A total of 1756 healthy men (by physical, blood, and semen exam) aged 18-51 yr of predominantly Caucasian (two thirds) or Asian (one third) descent were studied. This represents about 85% of all the published data. INTERVENTION(S) Men were treated with different preparations of testosterone, with or without various progestins. MAIN OUTCOME MEASURE Semen analysis was the main measure. RESULTS Progestin coadministration increased both the rate and extent of suppression. Caucasian men suppressed sperm output faster initially but ultimately to a less complete extent than did non-Caucasians. Younger age and lower initial blood testosterone or sperm concentration were also associated with faster suppression, but the independent effect sizes for age and baseline testicular function were relatively small. CONCLUSION Male hormonal contraceptives can be practically applied to a wide range of men but require coadministration of an androgen with a second agent (i.e. progestin) for earlier and more complete suppression of sperm output. Whereas considerable progress has been made toward defining clinically effective combinations, further optimization of androgen-progestin treatment regimens is still required.
Collapse
Affiliation(s)
- Peter Y Liu
- Department of Andrology, ANZAC Research Institute, University of Sydney and Concord Hospital, Concord, New South Wales 2139, Australia.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
68
|
Mruk DD. New perspectives in non-hormonal male contraception. Trends Endocrinol Metab 2008; 19:57-64. [PMID: 18291665 DOI: 10.1016/j.tem.2007.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 11/03/2007] [Accepted: 11/05/2007] [Indexed: 02/06/2023]
Abstract
As the world's population continues to soar, contraception has become increasingly important. Recently, men have expressed willingness to share the burden of family planning. Thus, safe, effective and reversible male contraceptives would satisfy an urgent need among couples. Currently, there are several promising non-hormonal contraceptives at various stages of research and development. In addition, major advances in genomic and proteomic research have been instrumental in identifying and characterizing genes and proteins expressed uniquely in the testis or other male reproductive organs, which might become 'druggable' targets for non-hormonal male contraceptive development in the future. Through committed research, advocacy and support, male contraceptives are likely to become a valuable addition to the current choices of family planning.
Collapse
Affiliation(s)
- Dolores D Mruk
- Population Council, Center for Biomedical Research, 1230 York Avenue, New York, NY 10065, USA.
| |
Collapse
|
69
|
Mruk DD, Cheng CY. Delivering non-hormonal contraceptives to men: advances and obstacles. Trends Biotechnol 2008; 26:90-9. [PMID: 18191256 PMCID: PMC4035909 DOI: 10.1016/j.tibtech.2007.10.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 10/25/2007] [Accepted: 10/30/2007] [Indexed: 02/06/2023]
Abstract
There have been major advances in male contraceptive research during the past two decades. However, for a contraceptive to be used by men, its safety requires more stringent scrutiny than therapeutic compounds for treatment of illnesses because the contraceptives will be used by healthy individuals for an extended period of time, perhaps decades. A wide margin is therefore required between the effective dose range and doses that cause toxicity. It might be preferable that a male contraceptive, in particular a non-hormone-based compound, is delivered specifically and/or directly to the testis and has a rapid metabolic clearance rate, reducing the length of exposure in the liver and kidney. In this article, we highlight the latest developments regarding contraceptive delivery to men and with the aim of providing useful information for investigators in future studies.
Collapse
Affiliation(s)
- Dolores D Mruk
- Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA.
| | | |
Collapse
|
70
|
Millar RP, Pawson AJ, Morgan K, Rissman EF, Lu ZL. Diversity of actions of GnRHs mediated by ligand-induced selective signaling. Front Neuroendocrinol 2008; 29:17-35. [PMID: 17976709 PMCID: PMC2667102 DOI: 10.1016/j.yfrne.2007.06.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 06/22/2007] [Accepted: 06/26/2007] [Indexed: 12/27/2022]
Abstract
Geoffrey Wingfield Harris' demonstration of hypothalamic hormones regulating pituitary function led to their structural identification and therapeutic utilization in a wide spectrum of diseases. Amongst these, Gonadotropin Releasing Hormone (GnRH) and its analogs are widely employed in modulating gonadotropin and sex steroid secretion to treat infertility, precocious puberty and many hormone-dependent diseases including endometriosis, uterine fibroids and prostatic cancer. While these effects are all mediated via modulation of the pituitary gonadotrope GnRH receptor and the G(q) signaling pathway, it has become increasingly apparent that GnRH regulates many extrapituitary cells in the nervous system and periphery. This review focuses on two such examples, namely GnRH analog effects on reproductive behaviors and GnRH analog effects on the inhibition of cancer cell growth. For both effects the relative activities of a range of GnRH analogs is distinctly different from their effects on the pituitary gonadotrope and different signaling pathways are utilized. As there is only a single functional GnRH receptor type in man we have proposed that the GnRH receptor can assume different conformations which have different selectivity for GnRH analogs and intracellular signaling proteins complexes. This ligand-induced selective-signaling recruits certain pathways while by-passing others and has implications in developing more selective GnRH analogs for highly specific therapeutic intervention.
Collapse
Affiliation(s)
- Robert P Millar
- MRC Human Reproductive Sciences Unit, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
| | | | | | | | | |
Collapse
|
71
|
Huyghe E, Nohra J, Vezzosi D, Bennet A, Caron P, Mieusset R, Bujan L, Plante P. Contraceptions masculines non déférentielles : revue de la littérature. Prog Urol 2007; 17:156-64. [PMID: 17489310 DOI: 10.1016/s1166-7087(07)92254-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
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.
Collapse
Affiliation(s)
- Eric Huyghe
- Service d'Urologie et Andrologie, Hôpital Paule de Viguier, Toulouse, France.
| | | | | | | | | | | | | | | |
Collapse
|
72
|
Abstract
Medical barriers to contraception can prevent women from obtaining, initiating, and continuing their contraceptive method of choice. The barriers include lack of appropriate counseling, delaying initiation for menses or laboratory tests, inappropriate contraindications or mandated warnings, untrained clinicians, and financial or regulatory barriers preventing access by low-income, undocumented, or adolescent women. These barriers may partially explain why almost half of pregnancies in the United States are unintended and occur predominantly in the small proportion of sexually active women not using contraception.
Collapse
Affiliation(s)
- Lawrence Leeman
- Department of Obstetrics and Gynecology, University of New Mexico, 2400 Tucker NE, Albuquerque, NM 87131, USA.
| |
Collapse
|
73
|
Walton MJ, Anderson RA, Kicman AT, Elton RA, Ossowska K, Baird DT. A diurnal variation in testicular hormone production is maintained following gonadotrophin suppression in normal men. Clin Endocrinol (Oxf) 2007; 66:123-9. [PMID: 17201811 DOI: 10.1111/j.1365-2265.2006.02696.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE A diurnal variation in serum testosterone in adult men is well recognized, but whether this occurs during exogenous testosterone administration and the degree to which it is endogenous to the testis is unclear. DESIGN A clinical research centre investigation of testicular function in normal men. PATIENTS Twenty normal men were recruited, 10 of whom were investigated during administration of testosterone with etonogestrel to suppress gonadotrophin secretion. MEASUREMENTS Hourly blood samples were taken over 24 h for measurement of testosterone, inhibin B, LH, FSH and cortisol. Urinary excretion of testosterone and the testicular steroid epitestosterone was also measured. RESULTS In the controls, a diurnal variation in serum testosterone and LH but not FSH was detected. The treated group had similar testosterone concentrations but showed no diurnal variation. Periodicity was also detected in inhibin B concentrations in 5 of the controls and in 9 of the treated group, who also showed synchrony not seen in the controls. Both groups showed diurnal variation in cortisol. Urinary testosterone excretion did not show a diurnal variation in either group, but this was apparent for epitestosterone with a morning peak in both groups despite the markedly lower excretion in the treated men. CONCLUSIONS The diurnal variation of testosterone in normal men is due to a change in secretion rather than in clearance and is largely LH driven. An endogenous rhythm in both testicular steroidogenesis (epitestosterone) and Sertoli cell function (inhibin B) is also present.
Collapse
Affiliation(s)
- Melanie J Walton
- Division of Reproductive and Developmental Science, University of Edinburgh, Edinburgh, UK
| | | | | | | | | | | |
Collapse
|
74
|
Walton MJ, Bayne RAL, Wallace I, Baird DT, Anderson RA. Direct effect of progestogen on gene expression in the testis during gonadotropin withdrawal and early suppression of spermatogenesis. J Clin Endocrinol Metab 2006; 91:2526-33. [PMID: 16621906 DOI: 10.1210/jc.2006-0222] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Testicular production of steroids and gametes is under gonadotropin support, but there is little information as to the molecular mechanisms by which these are regulated in the human. The testicular response to gonadotropin withdrawal is important for the development of effective contraceptive methods. OBJECTIVE Our objective was investigation of expression of genes in the normal human testis reflecting steroidogenesis, Sertoli cell function, and spermatogenesis after short-term gonadotropin withdrawal and the effects of activating testicular progesterone receptors. DESIGN AND SETTING We conducted a randomized controlled trial at a research institute. PATIENTS Thirty healthy men participated. INTERVENTIONS Subjects were randomized to no treatment or gonadotropin suppression by GnRH antagonist (cetrorelix) with testosterone (CT group) or with additional administration of the gestogen desogestrel (CTD group) for 4 wk before testicular biopsy. Gene expression was quantified by RT-PCR. RESULTS Both treatment groups showed similar suppression of gonadotropins and sperm production and markedly reduced expression of steroidogenic enzymes. Addition of progestogen in the CTD group resulted in reduced expression of 5alpha-reductase type 1 compared with both controls and the CT group. Inhibin-alpha and the spermatocyte marker acrosin-binding protein were significantly lower in the CTD but not CT groups, compared with controls, but did not differ between treated groups. Men who showed greater falls in sperm production also showed reduced expression of these three genes but not of the spermatid marker protamine 1. CONCLUSIONS These data provide evidence for direct progestogenic effects on the testis and highlight steroid 5alpha-reduction and disruption of spermiation as important components of the testicular response to gonadotropin withdrawal.
Collapse
Affiliation(s)
- Melanie J Walton
- Centre for Reproductive Biology, The Queen's Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, United Kingdom
| | | | | | | | | |
Collapse
|
75
|
Meriggiola MC, Cerpolini S, Bremner WJ, Mbizvo MT, Vogelsong KM, Martorana G, Pelusi G. Acceptability of an injectable male contraceptive regimen of norethisterone enanthate and testosterone undecanoate for men. Hum Reprod 2006; 21:2033-40. [PMID: 16731547 DOI: 10.1093/humrep/del094] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND We assessed attitudes towards and acceptability of male hormonal contraception among volunteers participating in a clinical trial of a prototype regimen, consisting of progestin and testosterone injections. METHODS After completing screening, eligible men were randomly assigned to the no-treatment group (n = 40) or to receive injections of norethisterone enanthate and testosterone undecanoate or placebo at different intervals (n = 50) according to a blocked randomization list. They underwent self-administered questionnaires. RESULTS The average age of the participants was approximately 28 years; most were involved in a stable relationship and had no children. Ninety-two percentage of the respondents thought that men and women should share responsibility for contraception and 75% said they would try a hormonal contraceptive if available. At the end of the treatment phase, 66% of the participants said that they would use such a method, and most rated its acceptability very highly; none reported it to be unacceptable. The injections themselves were indicated as the biggest disadvantage. No significant changes in sexual function or mood states were detected among the men who underwent hormone injections. CONCLUSIONS The contraceptive tested in this study was well accepted by the participants over the course of 1 year.
Collapse
Affiliation(s)
- M Cristina Meriggiola
- Obstetrics and Gynecology Unit, University of Bologna, S. Orsola Hospital, Bologna, Italy.
| | | | | | | | | | | | | |
Collapse
|
76
|
Abstract
The 'pre-testicular' suppression of gonadotrophins is the most likely approach for reversible therapeutic male fertility control to reach imminent clinical application. Maintenance of spermatogenesis depends on adequate gonadotrophin and intratesticular testosterone concentrations. Hormonal contraception for men interrupts this physiological axis by various means of gonadotrophin suppression; this interferes with spermatogonial differentiation and meiosis entry resulting in reversible azoospermia or severe oligozoospermia in virtually all men. Clinical trials have confirmed that high contraceptive efficacy, similar to female hormonal contraceptives, can be reliably attained with few side effects. However, the simultaneous suppression of Leydig cell steroidogenesis mandates the requirement for testosterone replacement in hormonal male contraception. Combination regimens of new synthetic progestins and androgens at various stages of development are being investigated with the lead products poised to go into phase III trials. Heterogeneity in response to spermatogenesis suppression has been observed within and between population; the mechanisms are unclear. This new method of reversible and effective contraception has registered high acceptability in surveys of both men and women. The recent entry of pharmaceutical companies into this area of research and development has considerably enhanced the prospects of translating years of academic efforts into new products which provide added family planning choice for many couples.
Collapse
Affiliation(s)
- Frederick C W Wu
- Department of Endocrinology, Manchester Royal Infirmary, University of Manchester, Oxford Rd, Manchester M13 9WL, United Kingdom
| |
Collapse
|
77
|
Liu PY, Swerdloff RS, Christenson PD, Handelsman DJ, Wang C. Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception: an integrated analysis. Lancet 2006; 367:1412-20. [PMID: 16650651 DOI: 10.1016/s0140-6736(06)68614-5] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Hormonal methods for safe, reliable, and reversible contraception based on the suppression of spermatogenesis could soon become available. We have investigated the rate, extent, and predictors of reversibility of hormonal male contraception. METHODS We undertook an integrated multivariate time-to-event analysis of data from individual participants in 30 studies published in 1990-2005, in which sperm output was monitored every month until recovery. The primary outcome was the time for the sperm concentration to recover to a threshold of 20 million per mL, an indicator of fertility. We undertook univariate and multivariate analyses, using Kaplan-Meier and Cox's methods. FINDINGS 1549 healthy eugonadal men who were white (n=965), Asian (almost all Chinese men; n=535), or of other origins (n=49) and aged 18-51 years underwent 1283.5 man-years of treatment and 705 man-years of post-treatment recovery. These data represented about 90% of all published data from individuals using androgen or androgen-progestagen regimens. The median times for sperm to recover to thresholds of 20, 10, and 3 million per mL were 3.4 months (95% CI 3.2-3.5), 3.0 months (2.9-3.1), and 2.5 months (2.4-2.7), respectively. Multivariate Cox's analysis showed higher rates of recovery with older age, Asian origin, shorter treatment duration, shorter-acting testosterone preparations, higher sperm concentrations at baseline, faster suppression of spermatogenesis, and lower blood concentrations of luteinising hormone at baseline. The typical probability of recovery to 20 million per mL was 67% (61-72) within 6 months, 90% (85-93) within 12 months, 96% (92-98) within 16 months, and 100% within 24 months. INTERPRETATION Hormonal male contraceptive regimens show full reversibility within a predictable time course. Various covariables affect the rate but not the extent of recovery, although their effect sizes are minor. These data are crucial for the further safe and practical development of such regimens.
Collapse
Affiliation(s)
- Peter Y Liu
- Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute, Torrance, CA, USA.
| | | | | | | | | |
Collapse
|
78
|
Matthiesson KL, McLachlan RI. Male hormonal contraception: concept proven, product in sight? Hum Reprod Update 2006; 12:463-82. [PMID: 16597629 DOI: 10.1093/humupd/dml010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Current male hormonal contraceptive (MHC) regimens act at various levels within the hypothalamic pituitary testicular axis, principally to induce the withdrawal of the pituitary gonadotrophins and in turn intratesticular androgen production and spermatogenesis. Azoospermia or severe oligozoospermia result from the inhibition of spermatogonial maturation and sperm release (spermiation). All regimens include an androgen to maintain virilization, while in many the suppression of gonadotrophins/spermatogenesis is augmented by the addition of another anti-gonadotrophic agent (progestin, GnRH antagonist). The suppression of sperm concentration to 1 x 10(6)/ml appears to provide comparable contraceptive efficacy to female hormonal methods, but the confidence intervals around these estimates remain relatively large, reflecting the limited number of exposure years reported. Also, inconsistencies in the rapidity and depth of spermatogenic suppression, potential for secondary escape of sperm into the ejaculate and onset of fertility return not readily explainable by analysis of subject serum hormone levels, germ cell number or intratesticular steroidogenesis, are apparent. As such, a better understanding of the endocrine and genetic regulation of spermatogenesis is necessary and may allow for new treatment paradigms. The development of an effective, consumer-friendly male contraceptive remains challenging, as it requires strong translational cooperation not only between basic scientists and clinicians but also between public and private sectors. At present, a prototype MHC product using a long-acting injectable testosterone and depot progestin is well advanced.
Collapse
Affiliation(s)
- Kati L Matthiesson
- Department of Obstetrics and Gynaecology, Prince Henry's Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Victoria 3168, Australia.
| | | |
Collapse
|
79
|
Kennedy CL, O'Bryan MK. N-ethyl-N-nitrosourea (ENU) mutagenesis and male fertility research. Hum Reprod Update 2006; 12:293-301. [PMID: 16436467 DOI: 10.1093/humupd/dmk004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Male infertility affects about 1 in 25 men in the western world. Conversely, there is an urgent requirement for additional male-based contraceptives, yet progress in both areas has been severely hampered by a lack of knowledge of the biochemistry and physiology of male reproductive function. It is only through a thorough knowledge of these processes that we can hope to insightfully regulate male reproductive function. Without doubt, mouse models will form an important foundation in any future process. In recent years, the chemical mutagen N-ethyl-N-nitrosourea (ENU) has been used widely to identify genes essential for a range of biological systems including male infertility. These studies have shown random mutagenesis is an attractive means of identifying key genes for male fertility. This technique has distinct, but complementary advantages compared to knockout technologies. Specifically, it allows the removal of researcher bias whereby only pre-conceived genes are tested for function; it produces mice with a guaranteed phenotype and allows for the production of allelic series of mice to dissect all aspects of gene function. ENU mouse mutagenesis programs will enable advances in the diagnosis and treatment of human male infertility and ultimately aid in the development of novel male-based contraceptives.
Collapse
Affiliation(s)
- C L Kennedy
- The Centre for Reproduction and Development, Monash Institute of Medical Research and the ARC Centre of Excellence in Biotechnology and Development, Monash University, Melbourne, Australia
| | | |
Collapse
|
80
|
Walton MJ, Anderson RAA. Male hormonal contraception: a safe option? Expert Rev Endocrinol Metab 2006; 1:25-32. [PMID: 30743766 DOI: 10.1586/17446651.1.1.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hormonal male contraception is based on the administration of testosterone alone or more likely with a progestogen. Testosterone has been used for several decades for the treatment of male hypogonadism, with an excellent safety record. Use as part of a contraceptive regimen by healthy people for prolonged periods will necessitate careful re-examination of safety issues. Although potential male contraceptive regimens have been investigated for many years, there have been mostly small-scale studies unable to assess safety. This is now changing, with larger studies of regimens underway. This, and the increasing involvement of the pharmaceutical industry, means that much more data will shortly be forthcoming and it is hoped that this will also provide valuable information relevant to normal male health. The main areas of interest are the cardiovascular system and the prostate, but bone health and body composition are also important, as are behavioral and psychologic aspects. The development of this field also allows the investigation of potential health benefits, which may be related to the use of synthetic androgens with tissue-selective metabolism or action.
Collapse
Affiliation(s)
- Melanie J Walton
- a The University of Edinburgh, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
| | - Richard A A Anderson
- b The University of Edinburgh, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
| |
Collapse
|
81
|
Ratcliffe KE, Fraser HM, Sellar R, Rivier J, Millar RP. Bifunctional gonadotropin-releasing hormone antagonist-progesterone analogs with increased efficacy and duration of action. Endocrinology 2006; 147:571-9. [PMID: 16223868 DOI: 10.1210/en.2004-1481] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GnRH peptide analogs are widely used to treat diverse clinical conditions. However, they have poor oral activity and exhibit rapid metabolic clearance, thus requiring injection and depot formulation. Because steroid hormones are bound to plasma proteins, we explored the possibility of conjugating hydroxylated progesterones to GnRH analogs to reduce metabolic clearance of the peptides. Conjugation of [D-Lys6]GnRH agonist to the alpha11-hydroxyl of alpha11-hydroxyl progesterone via a hemi-succinate bridge increased the plasma half-life after iv injection in rabbits by 3.6-fold while retaining high binding affinity, thus providing proof of concept. Five GnRH antagonists were then synthesized with 21-hydroxyprogesterone conjugated via C21-hydroxyl to positions six (conjugates A and B) and position seven (conjugates C and D) of GnRH antagonists. In the fifth compound the NH2 terminus of a GnRH antagonist lacking the first two amino acids was conjugated via the C21-hydroxyl to 21-hydroxyprogesterone (conjugate E). All five analogs bound to guinea pig progesterone binding globulin with relatively high affinities (264-1020 nM). Moreover, all five conjugates retained high progestogenic activity in stimulating a progesterone-response-element-driven chloramphenicol acetyltransferase reporter gene in the T47D breast cancer cell line. Conjugation via the epsilon-amino function of D-Lys6 (conjugates A and B) produced compounds with high binding affinity for the human GnRH receptor (15 and 7 nM) comparable to that of the unconjugated GnRH antagonists (4 and 26 nM). Conjugation via the epsilon-amino function of Lys7 (conjugates C and D) or the NH2 terminus of an N-terminally truncated antagonist (conjugate E) produced compounds of low binding affinity. Conjugates A and B also exhibited high functional antagonism of GnRH stimulation of inositol phosphate production in COS-7 cells expressing the human GnRH receptor (2.6 and 16 nM) compared with the unconjugated antagonists (1.3 and 122 nM). In accordance with their poor receptor binding affinity, conjugates C, D, and E had poor functional antagonism. Preliminary dose-finding studies in female marmosets showed transitory progesterone inhibition by 0.25 mg and prolonged suppression of 12 and 17 d by 0.5- and 1.0-mg doses. Injection of conjugate A in adult male marmosets (0.5 mg sc) rapidly suppressed plasma testosterone levels, which remained suppressed for at least 3 d. In contrast, the unconjugated parent antagonist alone or with progesterone suppressed testosterone for only 8 h to 1 d. The findings demonstrate that conjugation of progesterone to GnRH antagonists conveys plasma binding and progestogenic properties and increases their efficacy and duration of action in vivo. These new GnRH antagonists show promise as therapeutic agents for hormone-dependent diseases and as contraceptives.
Collapse
Affiliation(s)
- Karen E Ratcliffe
- Medical Research Council, Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh EH16 4TJ, Scotland, United Kingdom
| | | | | | | | | |
Collapse
|
82
|
Nandipati KC, Pasqualotto FF, Thomas AJ, Agarwal A. Relationship of interleukin-6 with semen characteristics and oxidative stress in vasectomy reversal patients. Andrologia 2005; 37:131-4. [PMID: 16164430 DOI: 10.1111/j.1439-0272.2005.00668.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
This prospective study was performed to evaluate the relationship between interleukin-6 (IL-6), oxidative stress and sperm function following vasectomy reversal. We included 22 patients who underwent vasectomy reversal and 15 healthy sperm donors (controls) with normal sperm morphology criteria. Levels of IL-6 in the semen were measured by the enzyme-linked immunosorbent assay, and levels of reactive oxygen species (ROS) and total antioxidant capacity were measured by the chemiluminescence assay. The mean sperm concentration in the vasectomy reversal group was significantly lower than control group (45.3 +/- 39.1 versus 63.1 +/- 28.5; P = 0.02). Motility was also significantly lower in the vasectomy reversal group (32.1 +/- 19.9 versus 54.6 +/- 18.9; P = 001). Levels of IL-6 were significantly higher in the vasectomy reversal group (2.09 +/- 0.87 versus 0.99 +/- 0.97; P = 0.007) as were mean ROS levels (2.25 +/- 0.97 versus 1.2 +/- 0.7; P = 0.009). Significant positive correlation was observed between the IL-6 and ROS levels in vasectomy reversal patients compared with donors (r = 0.41, P = 0.05 versus r = 0.38, P = 0.15). We conclude that patients who undergo vasectomy reversal have elevated levels of IL-6 and ROS, which may contribute to decreased sperm motility and concentration and possibly lead to sub-fertility.
Collapse
Affiliation(s)
- K C Nandipati
- Center for Advanced Research in Human Reproduction, Infertility, and Sexual Function, Glickman Urological Institute and Department of Obstetrics and Gynecology, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | | | | | | |
Collapse
|
83
|
Abstract
UNLABELLED Nonhormonal drugs for contraception in men may have advantages over hormonal methods. The nonhormonal methods can have more rapid onset and less interference with androgen-dependent functions. This systematic review summarizes the clinical studies evaluating nonhormonal drugs administered to men for contraception. Relevant clinical results were found for gossypol, which is derived from the cotton plant, and for extracts of Tripterygium, a plant used in Chinese traditional medicine. Randomized, controlled trials were available on the efficacy of gossypol and on the effect of gossypol on potassium levels. Gossypol had problems with low efficacy and toxicity. For Tripterygium, 2 observational studies described men who were treated for rheumatoid arthritis. Although sperm density was lower among those taking Tripterygium, later reports indicated some toxicity. Nonclinical research continues on isolates of Tripterygium. No clinical studies for contraception in men were found for nonhormonal vaccines or neem, which is also a plant used for medicinal purposes. Clinical trials studied injecting styrene maleic anhydride into the vas deferens, but no comparative data were provided. At this time, no safe and effective nonhormonal drug is available for contraception in men. TARGET AUDIENCE Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES After completion of this article, the reader should be able to state that the number of studies concerning the use of nonhormonal drugs for male contraception are very limited, point out that the two nonhormonal drugs used to a small degree have varying results and serious side effects, and recall that there are limited clinical studies on use of vas deferens injections and vaccines in humans.
Collapse
Affiliation(s)
- Laureen M Lopez
- Family Health International, Research Triangle Park, North Carolina 27709, USA.
| | | | | |
Collapse
|
84
|
Abstract
Although it is estimated that the population growth rate will decline to a replacement level by 2050, it is also now predicted that the total world population will reach 8.9 billion in that year -- far higher than the 2004 estimate of 6.4 billion. More than 26 billion new couples will need contraceptives in the next half century. Although a steady increase in contraceptive use has been observed in both developed and developing countries, the contraceptive needs of a high percentage of couples have not yet been met and the number of unplanned pregnancies continues to increase. The actual use of contraception differs from region to region. Although no new method has been registered for many years, several new products have been marketed during the last 5. Among these are new implants, medicated intrauterine systems, contraceptive vaginal rings, transdermal patches and several new combined oral contraceptive formulations. New contraceptive methods have been developed to meet the objectives of expanding contraceptive choices for both women and men and answering an unmet need for contraceptives with a long-term action that meet the expectations of consumers. Simplicity, reversibility and effectiveness are the desired features of a male contraceptive, but no new male contraceptive method is yet available. New areas of basic research include studies on genes, proteins and enzymes involved in the reproductive system. The new methods will be targeted to specific interactions within the reproductive system at the level of ovaries and testes, as well as between spermatozoa and ova. This futuristic approach still keeps in mind the need for better access to existing contraceptive methods, as well as the discovery of new contraceptives that are simple to use, safe, reversible and inexpensive. In the future, contraceptives may be combined with other medicinal agents to provide dual protection against both pregnancy and other preventable conditions, such as sexually transmitted infections.
Collapse
|
85
|
Abstract
Although effective contraceptive methods are available, the incidence of teenage pregnancies and consecutive pregnancy interruptions remains high in industrial nations, including Germany. There are several reasons for this high incidence. Apart from earlier sexual maturation, the absence of contraceptive use or the use of inefficient methods contributes mainly towards this increase. Existing contraceptive methods for men either show unsatisfying efficacy (coitus interruptus, use of condoms) or problems of reversibility (vasectomy), which limits their broader use. Of the different experimental approaches towards male contraception, the hormonal approach is closest to practical implementation. Androgens are an essential part of all experimental approaches to hormonal contraception in males; they cause suppression of spermatogenesis through gonadotropin suppression. Previous clinical trials have validated the concept of hormonal contraception in men. However, the application modalities and the ineffectiveness of all self-administered androgen preparations have been unacceptable for practical use. Therefore recent developments focus either on androgen implants or on injectable, long-acting testosterone esters in combination with progestins, which also suppress gonadotropin secretion. Over the last decades various combinations of androgen preparations with different progestins or GnRH antagonists have been tested in clinical trials. Of these, testosterone with either depot medroxyprogesterone acetate, norethisterone, desogestrel or etonogestrel have shown promising efficacy in phase II clinical trials. However, whether hormonal contraception might be given to adolescent males remains to be elucidated. This will have to be assessed once a hormonal contraceptive for men has reached the market. Special attention will need to be given to bone maturation as androgens at the prescribed doses might induce premature closure of the epiphyseal joints.
Collapse
Affiliation(s)
- Axel Kamischke
- Institut für Reproduktionsmedizin des Universitätsklinikums Münster, Domagkstrasse 11, DE-48129 Münster, Germany.
| | | |
Collapse
|
86
|
Hapgood JP, Sadie H, van Biljon W, Ronacher K. Regulation of expression of mammalian gonadotrophin-releasing hormone receptor genes. J Neuroendocrinol 2005; 17:619-38. [PMID: 16159375 DOI: 10.1111/j.1365-2826.2005.01353.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Gonadotrophin-releasing hormone (GnRH), acting via its cognate GnRH receptor (GnRHR), is the primary regulator of mammalian reproductive function, and hence GnRH analogues are extensively used in the treatment of hormone-dependent diseases, as well as for assisted reproductive techniques. In addition to its established endocrine role in gonadotrophin regulation in the pituitary, evidence is rapidly accumulating to support the expression and functional roles for two forms of GnRHR (GnRHR I and GnRHR II) in multiple and diverse extra-pituitary mammalian tissues and cells. These findings, together with findings indicating that mutations of the GnRHR are linked to the disease hypogonadotrophic hypogonadism and that GnRHRs play a direct role in neuronal migration and reproductive cancers, have presented new therapeutic targets and intensified research into the structure, function and mechanisms of regulation of expression of GnRHR genes. The present review focuses on the current knowledge on tissue-specific and hormonal regulation of transcription of mammalian GnRH receptor genes. Emerging insights, such as the discovery of diverse regulatory mechanisms in pituitary and extra-pituitary cell types, nonclassical mechanisms of steroid regulation, the use of composite elements for cell-specific expression, the increasing profile of hormones involved in regulation, the complexity of kinase pathways that target the GnRHR I gene, as well as species-differences, are highlighted. Although further research is necessary to understand the mechanisms of regulation of expression of GnRHR I and GnRHR II genes, the GnRHR is emerging as a potential target gene for facilitating cross-talk between neuroendocrine, immune and stress-response systems in multiple tissues via autocrine, paracrine and endocrine signalling.
Collapse
Affiliation(s)
- J P Hapgood
- Department of Biochemistry, University of Stellenbosch, Matieland, South Africa.
| | | | | | | |
Collapse
|
87
|
Saso L, Silvestrini B, Cheng CY. Preface: male infertility, from contraception to therapy. Contraception 2005. [DOI: 10.1016/j.contraception.2005.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
88
|
Brady BM, Amory JK, Perheentupa A, Zitzmann M, Hay CJ, Apter D, Anderson RA, Bremner WJ, Pollanen P, Nieschlag E, Wu FCW, Kersemaekers WM. A multicentre study investigating subcutaneous etonogestrel implants with injectable testosterone decanoate as a potential long-acting male contraceptive. Hum Reprod 2005; 21:285-94. [PMID: 16172147 DOI: 10.1093/humrep/dei300] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The combination of etonogestrel implants with injectable testosterone decanoate was investigated as a potential male contraceptive. METHODS One hundred and thirty subjects were randomly assigned to three treatment groups, all receiving two etonogestrel rods (204 mg etonogestrel) and 400 mg testosterone decanoate either every 4 weeks (group I, n = 42), or every 6 weeks (group II, n = 51) or 600 mg testosterone decanoate every 6 weeks (group III, n = 37) for a treatment period of 48 weeks. RESULTS One hundred and ten men completed 48 weeks of treatment. Sperm concentrations of <1 x 10(6)/ml were achieved in 90% (group I), 82% (group II) and 89% (group III) of subjects by week 24. Suppression was slower in group II, which also demonstrated more frequent escape from gonadotrophin suppression than groups I and III. Peak testosterone concentrations remained in the normal range throughout in all groups. Mean trough testosterone concentrations were initially subphysiological but increased into the normal range during treatment. Mean haemoglobin levels increased in group I, and a non-significant increase in weight and decline in high-density lipoprotein cholesterol was observed in all groups. Fourteen subjects discontinued treatment due to adverse events. CONCLUSIONS Subcutaneous etonogestrel implants in combination with injectable testosterone decanoate resulted in profound suppression of spermatogenesis that could be maintained for up to 1 year. Efficacy of suppression was less in group II, probably due to inadequate testosterone dosage. This combination has potential as a long-acting male hormonal contraceptive.
Collapse
Affiliation(s)
- B M Brady
- Centre for Reproductive Biology, University of Edinburgh, Edinburgh EH16 4TJ, UK.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
89
|
Abstract
Although a steady increase in contraceptive use has been observed in developed and less-developed countries, the contraceptive needs of a significant proportion of couples have not yet been met, resulting in an increase in unplanned pregnancies. Several new contraceptive products have reached the market during the past few years. Among these are new implants, a medicated intrauterine device, contraceptive vaginal rings, transdermal patches and several new regimen of combined oral contraceptives. These new or improved methods have been developed to expand the contraceptive choices available to women and men as well as to respond to the unmet need for contraceptives with long-term activity. New targets are being identified both in the ovary and the testes for a more specific non-hormonal contraception. This futuristic approach still keeps in mind the need for better access to existing contraceptive methods, as well as the discovery of new contraceptives that are simple to use, safe, reversible and inexpensive. In recent years, there has been great interest in agents that provide dual protection against pregnancy and sexually transmitted infections (STI), especially human immunodeficiency virus (HIV). A contraceptive method providing dual medical benefits might increase motivation for consistent use, thus reducing contraceptive failures and unwanted pregnancies.
Collapse
Affiliation(s)
- Regine Sitruk-Ware
- Center for Biomedical Research, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
| |
Collapse
|
90
|
Ly LP, Liu PY, Handelsman DJ. Rates of suppression and recovery of human sperm output in testosterone-based hormonal contraceptive regimens*. Hum Reprod 2005; 20:1733-40. [PMID: 15860500 DOI: 10.1093/humrep/deh834] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Practical hormonal male contraceptive regimens are likely to have delayed onset and offset of reliable contraception dictated by the length of the spermatogenic cycle and clearance rate of pre-formed sperm from the ductular system. While delayed onset of contraceptive efficacy is an accepted feature of vasectomy, reliable time estimates for a hormonal male contraceptive of time to onset and offset of reliable contraception and of resumption of normal male fertility are required. METHODS AND RESULTS We utilized the sperm output data from three male contraceptive efficacy studies to define quantitative estimates of suppression and recovery rates from an androgen alone (testosterone enanthate) and an androgen/progestin (testosterone/depot medroxyprogesterone acetate) study. Using nearly 14,000 semen samples from World Health Organization (WHO) studies #85921 and #89903 with identical protocols, the rate of suppression of sperm output was best modelled as a two-parameter, single exponential decay function with effective half-time to suppression of 5.5 weeks and times of 6.8 weeks to 10 x 10(6)/ml, 8.7 weeks to 5 x 10(6)/ml, 10.0 weeks to 3 x 10(6)/ml and 13.0 weeks to 1 x 10(6)/ml. The rate of recovery using absolute sperm concentration was best modelled as a three-parameter, sigmoidal curve with effective time to reach half of the recovery plateau of 10.5 weeks and times of 9.0 weeks to 3 x 10(6)/ml, 9.9 weeks to 5 x 10(6)/ml, 11.5 weeks to 10 x 10(6)/ml, and 13.6 weeks to 20 x 10(6)/ml. Using relative sperm output, defined as a percentage of the participants' own baseline, recovery approached an asymptotic plateau of approximately 85% of geometric mean pre-treatment sperm concentration. In the combination androgen/progestin study, suppression rate was significantly faster (effective time to reach half maximal suppression of 3.0 weeks) and recovery significantly slower (effective time to reach half of recovery plateau of 14.7 weeks) and less complete (asymptotic recovery plateau of 43% of baseline) than in the androgen-alone WHO studies. CONCLUSION These findings therefore provide large sample estimates of the suppression and recovery rates from an androgen-alone hormonal male contraceptive regimen as a basis for comparison with other second-generation combination androgen/progestin regimens that are the most promising approach to developing practical male hormonal regimens.
Collapse
Affiliation(s)
- Lam P Ly
- Departments of Andrology, Concord Hospital & ANZAC Research Institute, University of Sydney, Sydney NSW 2139, Australia
| | | | | |
Collapse
|
91
|
Lessard C, Pendola JK, Hartford SA, Schimenti JC, Handel MA, Eppig JJ. New mouse genetic models for human contraceptive development. Cytogenet Genome Res 2005; 105:222-7. [PMID: 15237210 DOI: 10.1159/000078192] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Accepted: 11/19/2003] [Indexed: 11/19/2022] Open
Abstract
Genetic strategies for the post-genomic sequence age will be designed to provide information about gene function in a myriad of physiological processes. Here an ENU mutagenesis program (http://reprogenomics.jax.org) is described that is generating a large resource of mutant mouse models of infertility; male and female mutants with defects in a wide range of reproductive processes are being recovered. Identification of the genes responsible for these defects, and the pathways in which these genes function, will advance the fields of reproduction research and medicine. Importantly, this program has potential to reveal novel human contraceptive targets.
Collapse
Affiliation(s)
- C Lessard
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | | | | | | | | | | |
Collapse
|
92
|
Valdes-Socin H, Salvi R, Daly AF, Gaillard RC, Quatresooz P, Tebeu PM, Pralong FP, Beckers A. Hypogonadism in a patient with a mutation in the luteinizing hormone beta-subunit gene. N Engl J Med 2004; 351:2619-25. [PMID: 15602022 DOI: 10.1056/nejmoa040326] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A 30-year-old man who presented with delayed puberty and infertility was found to have hypogonadism associated with an absence of circulating luteinizing hormone. The patient had a homozygous missense mutation in the gene that encodes the beta subunit of luteinizing hormone (Gly36Asp), a mutation that disrupted a vital cystine knot motif and abrogated the heterodimerization and secretion of luteinizing hormone. Treatment with human chorionic gonadotropin increased circulating testosterone, promoted virilization, and was associated with the appearance of normal spermatozoa in low concentrations. This case illustrates the important physiological role that luteinizing hormone plays in male sexual maturation and fertility.
Collapse
Affiliation(s)
- Hernán Valdes-Socin
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, Domaine du Sart-Tilman, Liege, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
93
|
Brady BM, Walton M, Hollow N, Kicman AT, Baird DT, Anderson RA. Depot testosterone with etonogestrel implants result in induction of azoospermia in all men for long-term contraception. Hum Reprod 2004; 19:2658-67. [PMID: 15333595 DOI: 10.1093/humrep/deh491] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Combined testosterone and progestogen preparations are a promising approach to male hormonal contraception. We investigated the effect of s.c. etonogestrel with depot testosterone on spermatogenesis in normal men over a period of 48 weeks. METHODS Fifteen healthy men received three s.c. 68 mg etonogestrel implants. Testosterone pellets (400 mg) were administered at 12 weekly intervals. RESULTS Nine men completed 48 weeks of treatment. Four subjects chose to discontinue after 6 months, one man withdrew from the study early for personal reasons and one was withdrawn due to illness. Sperm concentrations of <1 x 10(6)/ml were achieved in all men by 16 weeks of treatment. All men became azoospermic, although the time to achieve this varied from 8 to 28 weeks. Azoospermia was maintained in eight of the nine men treated for 48 weeks, one subject showing partial recovery from 40 weeks. Testosterone levels remained in the physiological range throughout. Treatment did not result in weight gain, change in body composition or decline in high-density lipoprotein cholesterol concentrations. CONCLUSIONS The combination of three etonogestrel implants with depot testosterone results in rapid and consistent suppression of spermatogenesis. This can be maintained for up to 1 year and may therefore be a suitable approach for a long-acting male hormonal contraceptive.
Collapse
Affiliation(s)
- B M Brady
- Contraceptive Development Network and MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, University of Edinburgh, UK
| | | | | | | | | | | |
Collapse
|
94
|
Mruk DD, Cheng CY. Sertoli-Sertoli and Sertoli-germ cell interactions and their significance in germ cell movement in the seminiferous epithelium during spermatogenesis. Endocr Rev 2004; 25:747-806. [PMID: 15466940 DOI: 10.1210/er.2003-0022] [Citation(s) in RCA: 596] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Spermatogenesis is the process by which a single spermatogonium develops into 256 spermatozoa, one of which will fertilize the ovum. Since the 1950s when the stages of the epithelial cycle were first described, reproductive biologists have been in pursuit of one question: How can a spermatogonium traverse the epithelium, while at the same time differentiating into elongate spermatids that remain attached to the Sertoli cell throughout their development? Although it was generally agreed upon that junction restructuring was involved, at that time the types of junctions present in the testis were not even discerned. Today, it is known that tight, anchoring, and gap junctions are found in the testis. The testis also has two unique anchoring junction types, the ectoplasmic specialization and tubulobulbar complex. However, attention has recently shifted on identifying the regulatory molecules that "open" and "close" junctions, because this information will be useful in elucidating the mechanism of germ cell movement. For instance, cytokines have been shown to induce Sertoli cell tight junction disassembly by shutting down the production of tight junction proteins. Other factors such as proteases, protease inhibitors, GTPases, kinases, and phosphatases also come into play. In this review, we focus on this cellular phenomenon, recapping recent developments in the field.
Collapse
Affiliation(s)
- Dolores D Mruk
- Population Council, Center for Biomedical Research, New York, New York 10021, USA.
| | | |
Collapse
|
95
|
Abstract
'Classical' genomic progesterone receptors appear relatively late in phylogenesis, i.e. it is only in birds and mammals that they are detectable. In the different species, they mediate manifold effects regarding the differentiation of target organ functions, mainly in the reproductive system. Surprisingly, we know little about the physiology, endocrinology, and pharmacology of progesterone and progestins in male gender or men respectively, despite the fact that, as to progesterone secretion and serum progesterone levels, there are no great quantitative differences between men and women (at least outside the luteal phase). In a prospective cohort study of 1026 men with and without cardiovascular disease, we were not able to demonstrate any age-dependent change in serum progesterone concentrations. Progesterone influences spermiogenesis, sperm capacitation/acrosome reaction and testosterone biosynthesis in the Leydig cells. Other progesterone effects in men include those on the central nervous system (CNS) (mainly mediated by 5alpha-reduced progesterone metabolites as so-called neurosteroids), including blocking of gonadotropin secretion, sleep improvement, and effects on tumors in the CNS (meningioma, fibroma), as well as effects on the immune system, cardiovascular system, kidney function, adipose tissue, behavior, and respiratory system. A progestin may stimulate weight gain and appetite in men as well as in women. The detection of progesterone receptor isoforms would have a highly diagnostic value in prostate pathology (benign prostatic hypertrophy and prostate cancer). The modulation of progesterone effects on typical male targets is connected with a great pharmacodynamic variability. The reason for this is that, in men, some important effects of progesterone are mediated non-genomically through different molecular biological modes of action. Therefore, the precise therapeutic manipulation of progesterone actions in the male requires completely new endocrine-pharmacological approaches.
Collapse
|
96
|
Hild SA, Attardi BJ, Reel JR. The Ability of a Gonadotropin-Releasing Hormone Antagonist, Acyline, to Prevent Irreversible Infertility Induced by the Indenopyridine, CDB-4022, in Adult Male Rats: The Role of Testosterone1. Biol Reprod 2004; 71:348-58. [PMID: 15044265 DOI: 10.1095/biolreprod.103.026989] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Intratesticular testosterone (ITT) is known to play a critical role in the maintenance of spermatogenesis. We have used acyline, a GnRH antagonist, to suppress testosterone (T) production, and acyline and T implants to study the prevention of irreversible infertility induced by CDB-4022. Vehicle or acyline was administered to proven fertile male rats (n = 5/group) at a dose (210 microg/day) that completely suppressed (P < 0.05) T production, as measured by serum T, and testicular function, either before, concurrent with, or after vehicle or a single oral dose of 2.5 mg CDB-4022/kg (Week 0). Vehicle-treated males remained fertile, whereas acyline-treated males exhibited transitory infertility. CDB-4022 alone caused irreversible infertility in all males. Importantly, CDB-4022-treated males recovered fertility when acyline was started before CDB-4022 (Weeks -4 to 0; Weeks -4-9), but not when acyline was administered concurrently with or after CDB-4022 (Weeks 0-9; Weeks 10-19). At the end of this study (Week 34), testes weights, spermatid head counts (SHC), and tubule differentiation indices (TDI) were suppressed (P < 0.05) in infertile CDB-4022-treated males, but in rats that recovered fertility, these parameters were similar (P > 0.05) to those in vehicle-treated males. In addition, serum inhibin B and epididymal androgen-binding protein levels were nondetectable in infertile CDB-4022-treated rats. To test whether suppression of ITT was critical for prevention of CDB-4022-induced infertility, proven fertile rats (n = 7-8/group) received vehicle, acyline alone, or acyline and a T implant for 4 wk before CDB-4022 (Week 0). The T implant increased ITT in acyline-treated rats. Although ITT was lower (P < 0.05) in the T-implanted males than in untreated rats, it was sufficient to sustain spermiogenesis. Serum rFSH levels were also elevated in rats treated with acyline + T as compared with acyline alone during the treatment interval, but rFSH was still lower than in vehicle-treated rats. Rats in all treatment groups were rendered infertile initially, but the acyline + CDB-4022-treated rats recovered fertility by Week 10. In contrast, rats treated with CDB-4022 alone or acyline + T + CDB-4022 remained infertile until at least Week 16. Testes weights, SHC, and TDI were within normal ranges for acyline + CDB-4022-treated rats, but were decreased (P < 0.05) in CDB-4022- or acyline + T + CDB-4022-treated rats. Serum inhibin B levels were nondetectable by Week 1 in males rendered irreversibly infertile by CDB-4022; levels increased transiently and returned to baseline in rats protected by acyline pretreatment. These data indicate that pretreatment with acyline was able to prevent irreversible infertility in CDB-4022-treated rats, whereas posttreatment with acyline did not promote spermatogonial differentiation, as has been observed by others in rats that received GnRH analogs and various other testicular toxicants. Suppression of ITT and possibly rFSH by acyline appeared to be crucial in preventing irreversible infertility induced by CDB-4022. In this regard, our results are similar to those of investigators who have studied other testicular toxicants. Continued development of CDB-4022 as a potential male contraceptive will depend largely on its safety profile and whether its antispermatogenic activity is reversible in primates.
Collapse
|
97
|
Abstract
GnRH and its analogs are used extensively for the treatment of hormone-dependent diseases and assisted reproductive techniques. They also have potential as novel contraceptives in men and women. A thorough delineation of the molecular mechanisms involved in ligand binding, receptor activation, and intracellular signal transduction is kernel to understanding disease processes and the development of specific interventions. Twenty-three structural variants of GnRH have been identified in protochordates and vertebrates. In many vertebrates, three GnRHs and three cognate receptors have been identified with distinct distributions and functions. In man, the hypothalamic GnRH regulates gonadotropin secretion through the pituitary GnRH type I receptor via activation of G(q). In-depth studies have identified amino acid residues in both the ligand and receptor involved in binding, receptor activation, and translation into intracellular signal transduction. Although the predominant coupling of the type I GnRH receptor in the gonadotrope is through productive G(q) stimulation, signal transduction can occur via other G proteins and potentially by G protein-independent means. The eventual selection of intracellular signaling may be specifically directed by variations in ligand structure. A second form of GnRH, GnRH II, conserved in all higher vertebrates, including man, is present in extrahypothalamic brain and many reproductive tissues. Its cognate receptor has been cloned from various vertebrate species, including New and Old World primates. The human gene homolog of this receptor, however, has a frame-shift and stop codon, and it appears that GnRH II signaling occurs through the type I GnRH receptor. There has been considerable plasticity in the use of different GnRHs, receptors, and signaling pathways for diverse functions. Delineation of the structural elements in GnRH and the receptor, which facilitate differential signaling, will contribute to the development of novel interventive GnRH analogs.
Collapse
Affiliation(s)
- Robert P Millar
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, Scotland, United Kingdom.
| | | | | | | | | | | |
Collapse
|
98
|
Abstract
The use of androgens is an essential part of all experimental approaches to hormonal male contraception and involves the suppression of gonadotrophins, leading to inhibition of spermatogenesis. Although clinical trials have proven the concept of hormonal male contraception, their modalities have been unacceptable for practical use for several reasons. Because the efficacy of all self-administered androgen preparations has been disappointing, recent studies have focused on either androgen implants or injectable, long-acting testosterone esters such as testosterone undecanoate. However, in contrast to East Asian men, only two-thirds of Caucasian men respond to such androgen-based regimens with the desired azoospermia (no sperm produced), and thus additional agents are required. Over the past decades various combinations of androgen preparations with different progestins or gonadotrophin-releasing-hormone antagonists have been tested in clinical trials. Of these, testosterone administered in combination with either depot medroxyprogesterone acetate, norethisterone enanthate, desogestrel or etonogestrel have shown promising efficacy.
Collapse
Affiliation(s)
- Axel Kamischke
- Institute of Reproductive Medicine of the University, Domagkstr. 11, D-48129, Muenster, Germany
| | | |
Collapse
|
99
|
Abstract
Using molecular, cellular, and genetic approaches, recent studies examining the role of the bone morphogenetic protein (BMP) family of growth factors in the reproductive system have led to significant breakthroughs in our understanding of mammalian reproduction and fertility. Gene expression studies have revealed that key components of the BMP system (ligands, receptors, signaling molecules, and binding proteins) exhibit coordinated spatial and temporal expression patterns in fundamental cell types throughout the reproductive system. Availability of recombinant BMPs has enabled functional studies that have demonstrated important biological activities of BMPs in controlling cellular proliferation, differentiation, and apoptosis in reproductive tissues. The physiological importance of the BMP system for mammalian reproduction has been further highlighted by the elucidation of the aberrant reproductive phenotypes of animals with naturally occurring mutations or targeted deletions of certain BMP family genes. Collectively, these studies have established the concept that the BMP system plays a crucial role in fertility in female and male mammals. The purpose of this article is to review the evidence underpinning the importance of the BMP system in mammalian reproduction.
Collapse
Affiliation(s)
- Shunichi Shimasaki
- Department of Reproductive Medicine, University of California San Diego, School of Medicine, La Jolla, California 92093-0633, USA.
| | | | | | | |
Collapse
|
100
|
Abstract
BACKGROUND Male hormonal contraception has been an elusive goal. Administration of sex steroids to men can shut off sperm production through effects on the pituitary and hypothalamus. However, this approach also decreases production of testosterone, so "add-back" therapy is needed. OBJECTIVES To summarize all randomized controlled trials of male hormonal contraception. SEARCH STRATEGY We searched the computerized databases Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Popline, and LILACS (each from inception to February, 2003) for randomized controlled trials of hormonal contraception in men. We wrote to authors of identified trials to seek unpublished or published trials that we might have missed. SELECTION CRITERIA We included all randomized controlled trials in any language that compared a steroid hormone with another contraceptive. We excluded non-steroidal male contraceptives, such as gossypol. We included both placebo and active-regimen control groups. All trials identified included only healthy men with normal semen analyses. DATA COLLECTION AND ANALYSIS Azoospermia (absence of spermatozoa on semen examination) was the primary outcome measure. Data were insufficient to examine pregnancy rates and side effects. MAIN RESULTS The proportion of men who achieved azoospermia varied widely in reports to date. Few significant differences emerged from these trials. Levonorgestrel implants combined with injectable testosterone enanthate (100 mg IM) was significantly more effective than was levonorgestrel 125 mcg by mouth daily combined with testosterone patches (10 mg/d) (OR for azoospermia with the oral levonorgestrel regimen 0.03; 95%CI 0.00-0.29). The addition of levonorgestrel 500 mcg by mouth daily improved the effectiveness of testosterone enanthate 100 mg IM weekly by itself (OR for azoospermia with the combined regimen 4.0; 95%CI 1.00-15.99). Several regimens, including testosterone alone and GnRH agonists and antagonists, had disappointing results. REVIEWERS' CONCLUSIONS No male hormonal contraceptive is ready for clinical use. All trials published to date have been small exploratory studies. As a result, their power to detect important differences has been limited and their results imprecise. In addition, the definition of oligospermia has been imprecise or inconsistent in many reports. To avoid bias, future trials need more attention to the methodological requirements for randomized controlled trials. Trials with adequate power would also be helpful.
Collapse
Affiliation(s)
- D Grimes
- Family Health International, P. O. Box 13950, Research Triangle Park, North Carolina 27709, USA.
| | | | | | | | | |
Collapse
|