sperm capacitation

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WordNet

the male reproductive cell; the male gamete; "a sperm is mostly a nucleus surrounded by little other cellular material" (同)sperm_cell, spermatozoon, spermatozoan

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/03/07 20:31:38」(JST)

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Capacitation is the penultimate^[1] step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte. This step is a biochemical event; the sperm move normally and look mature prior to capacitation. In vivo this step typically occurs after ejaculation, in the female reproductive tract. In vitro, capacitation can occur by incubating sperms that have either undergone ejaculation or have been extracted from the epididymis in a defined medium for several hours.

The uterus aids in the steps of capacitation by secreting sterol-binding albumin, lipoproteins, proteolytic and glycosidasic enzymes such as heparin.

Non-mammalian spermatozoa do not require this capacitation step and are ready to fertilize an oocyte immediately after release from the male. After this capacitation the sperm must undergo activation involving the acrosome reaction.

Capacitation

Capacitation involves the destabilisation of the acrosomal sperm head membrane allowing greater binding between sperm and oocyte. This change is facilitated by the removal of sterols (e.g. cholesterol) and non-covalently bound epididymal/seminal glycoproteins. The result is a more fluid membrane with an increased permeability to Ca²⁺.

An influx of Ca²⁺ produces increased intracellular cAMP levels and thus, an increase in motility. Hyperactivation coincides with the onset of capacitation and is the result of the increased Ca²⁺ levels. The tripeptide FPP (fertilization promoting peptide) produced by the male is essential for capacitation (high levels of FPP prevent capacitation, the proper concentration occurs after ejaculation in the female reproductive tract where the concentration drops after mixing with vaginal secretions and/or becomes less active due to the pH of the vagina). It has a synergistic stimulatory effect with adenosine that increases adenylyl cyclase activity in the sperm. FPP is found in the seminal fluid (FPP produced in prostate gland), and comes into contact with the spermatozoa upon ejaculation.

Discovery

The discovery of this process was independently reported in 1951 by both Min Chueh Chang^[2] and Colin Russell Austin.^[3]^[4]

Historically, the term "capacitation" has evolved in meaning^[how?] and this should be taken into account when consulting sources.

Footnotes

^ Essential Reproduction, Johnson, 6th edition, Blackwell Publishing
^ Chang, M. C. (1951) “Fertilizing capacity of spermatozoa deposited into the fallopian tubes,” Nature, vol. 168, pages 697-698.
^ Austin, C. R. (1951) “Observations of the penetration of sperm into the mammalian egg,” Australian Journal of Scientific Research, Series B, vol. 4, pages 581-596.
^ Austin, Colin Russell: obituary: “Colin Austin,” Australian Academy of Science Newsletter, No. 60, page 11 (August–November 2004). Available on-line at: http://www.science.org.au/newsletters/aas60.pdf .

References

Beaudin, Stacey; Kipta, Donna; and Orr, Annamarie. (October 9, 1996). Current research into sperm capacitation: An Essay on Visconti, et al. Development 121: 1129-1150 (1995). Verified availability 2005-04-06.
Visconti, Pablo E.; Bailey, Janice L.; Moore, Grace D.; Pan, Dieyun; Olds-Clarke, Patricia; and Kopf, Gregory S. (1995). Capacitation of mouse spermatozoa: I. Correlation between the capacitation state and protein tyrosine phosphorylation. Development 121, 1129-1137. PMID 7743926. full article text available on-line

External links

Sperm Capacitation at the US National Library of Medicine Medical Subject Headings (MeSH)

UpToDate Contents

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2. 男性不妊症の治療 treatment of male infertility
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English Journal

Proteomic characteristics of human sperm cryopreservation.

Wang S, Wang W, Xu Y, Tang M, Fang J, Sun H, Sun Y, Gu M, Liu Z, Zhang Z, Lin F, Wu T, Wang Z, Zhang W, Yin C.SourceState Key Laboratory of Reproductive Medicine, Department of Urology, First Affiliated Hospital of Nanjing Medical University, P. R. China.
Proteomics.Proteomics.2013 Nov 20. doi: 10.1002/pmic.201300225. [Epub ahead of print]
Human sperm cryopreservation in assisted reproductive technology is the only proven method that enables infertile men to father their own children. However, freezing and thawing reduces spermatozoon motility, viability, and fertilizing ability. An association between dysfunctional spermatozoa due to
PMID 24259508

Alkaline phosphatase in boar sperm function.

Bucci D, Isani G, Giaretta E, Spinaci M, Tamanini C, Ferlizza E, Galeati G.SourceDipartimento di Scienze Mediche Veterinarie (DIMEVET), Università degli Studi di Bologna, Ozzano dell'Emilia (BO), Italy.
Andrology.Andrology.2013 Nov 19. doi: 10.1111/j.2047-2927.2013.00159.x. [Epub ahead of print]
Alkaline phosphatase (AP) catalyses the detachment of phosphate residues from different substrates. Its activity has been demonstrated in seminal plasma and spermatozoa from porcine and other mammalian species; anyway, the role of AP in male reproduction has not been clarified yet and the aim of thi
PMID 24249651

Bovine oviduct epithelial cells down-regulate phagocytosis of sperm by neutrophils: Prostaglandin E2 as a major physiological regulator.

Marey MA, Liu J, Kowsar R, Haneda S, Matsui M, Sasaki M, Shimizu T, Hayakawa H, Wijayagunawardane MP, Hussein FM, Miyamoto A.SourceM Marey, Theriogenology Department, Damanhur University, Behera, Egypt.
Reproduction (Cambridge, England).Reproduction.2013 Nov 19. [Epub ahead of print]
This study aimed to investigate the presence of polymorphonuclear neutrophils (PMNs) in bovine oviduct fluid under physiological conditions, and to determine the possible role of bovine oviduct epithelial cells (BOECs) in regulation of the phagocytic activity of PMNs for sperm. During the pre-ovulat
PMID 24255155

Japanese Journal

Ca²⁺ and cAMP regulations of microtubule sliding in hyperactivated motility of bull spermatozoa

Proceedings of the Japan Academy, Series B 91(3), 99-108, 2015
… Under these conditions, the microtubule sliding of bull sperm flagella was investigated by disintegrating the sperm flagella with MgATP2− after extracting their plasma membrane and mitochondria. …
NAID 130004802306