Experimental methods of contraception.

G S Grubb

Home/Archive/PubMed

PubMed · 1878506

Experimental methods of contraception.

G S Grubb

View original source ↗Export metadata ↓

Abstract

While most new contraceptives currently in development incorporate existing contraceptive agents into new delivery systems, several types of contraceptives with novel mechanisms of action are making steady progress. The antiprogestin mifepristone (better known as RU 486) is being tested as an ovulation inhibitor, as a once-a-month pill, and as a postcoital contraceptive. An antiestrogen, Centchroman (Hindustan Latex, India), is in use in India as a once-a-week, nonsteroidal pill. The development of more potent pituitary gonadotropin antagonists has improved their potential to block ovulation in women and to inhibit spermatogenesis in men (which requires concurrent administration of testosterone). Another promising male contraceptive is an intraluminal vas occlusion plug tested extensively in China that can be removed with no apparent detriment to future fertility. Finally, several types of immunocontraceptives could become the most specific form of fertility control by directing an antibody response against the fertilized or unfertilized egg or against sperm.

Explore related subjects

Contraception, Immunologic Contraceptive Agents Female Gonadotropin-Releasing Hormone Humans Male Mifepristone Pregnancy Sterilization, Reproductive Testosterone Journal Article Review

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

G S Grubb. 1991. Experimental methods of contraception.. https://pubmed.ncbi.nlm.nih.gov/1878506/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1998

Testis-specific proteins and their role in contraceptive vaccine development.

Development of a vaccine(s) based on sperm antigens represents a promising approach for contraception. The utility of an antigen in immunocontraception is contingent upon its testis/sperm specificity and involvement in spermatogenesis and/or fertilization. The aim of the present article is to review the information regarding the proteins that have been reported to be testis/sperm-specific and may have an important function in spermatogenesis and/or fertilization. The potential role of these proteins in the development an antisperm contraceptive vaccine(s) is discussed.

Contraception, Immunologic↗

PubMed1997

Sperm antigens and their use in the development of an immunocontraceptive.

PROBLEM: Overpopulation is a global problem of significant magnitude, with grave implications for the future. World population is predicted to reach 10 billion people by the year 2050, an increase of more than 75% over the current population. Development of new contraceptives is necessary, since current forms of birth control are unavailable to many individuals due to sociological, financial, or educational limitations. METHODS: In an effort to identify new contraceptive alternatives, sperm-specific antigens are under the investigation as the basis for immunological regulation of fertility through contraceptive immunization. Anti-sperm antibodies (ASA) inhibit sperm function in vitro, induce infertility in experimental models, and have been implicated in some cases of clinical infertility. Furthermore, the development of ASA in vasectomized men does not lead to physiological complications despite the persistence of these antibodies for years; thus, ASA induced by immunization of men and women may be similarly harmless. Immunization has several conceptual advantages as a method of fertility regulation. Employment of non-pharmacologically active agents, convenience of administration, low cost, and the potential for relatively long-lasting yet reversible effects. RESULTS: Various approaches have been taken to identify candidate sperm antigens for immunocontraceptive development. Studies that utilized monoclonal antibodies and polyclonal antisera generated against sperm preparations have identified such promising candidates as PH-20, fertilin, SP-17, and SP-10. In animal model, 100% contraceptive effects were induced following PH-20 immunization and the effects were reversible. More recently, ASA from the sera of infertile patients were employed to identify several candidates as expressed by testis cDNA libraries. Perhaps the most extensively characterized and effective immunogen candidate identified thus far is lactate dehydrogenase-C4 (LDH-C4). Active immunization with LDH-C4 suppressed fertility in a variety of mammalian species, including primates, and the reversibility of these effects was demonstrated. CONCLUSION: The successful results obtained thus far support the feasibility of an effective immunocontraceptive and indicate the importance for continued investigation of additional sperm antigens as contraceptive immunogen candidates.

Contraception, Immunologic↗

PubMed1996

Luminal and glandular endometrial epithelium express integrins differentially throughout the menstrual cycle: implications for implantation, contraception, and infertility.

PROBLEM: Integrins belong to a family of cell adhesion molecules that are present on virtually all cells. The temporal and spatial expression of these important proteins on the human endometrium suggests that certain integrins may participate in the cascade of molecular events leading to successful implantation. METHODS: Using immunohistochemistry, we studied the expression of 12 different integrins in up to 600 samples of human endometrium throughout the menstrual cycle. Intensity and distribution of staining was determined using the semiquantitative HSCORE, with specific focus on the differences between glandular and luminal expression. RESULTS: We noted that the glandular and luminal epithelium undergo independent alterations in integrin expression throughout the menstrual cycle. Specifically, glandular epithelium express certain integrins only during the window of implantation, while luminal epithelium down-regulate certain integrins during this time. The expression of one integrin (the alpha v beta 3 vitronectin receptor) on both luminal and glandular epithelium coincides with the time of embryo attachment; aberrant expression of this integrin is associated with infertility. CONCLUSION: It appears that the endometrium is a unique tissue with regard to the number of integrins that undergo temporal and spatial changes during the menstrual cycle. These data may offer new directions for the development of a novel contraceptive approach targeted to the endometrium as well as a better understanding of occult causes of infertility in women.

Contraception, Immunologic↗