نتایج جستجو برای: spermatogenesis

تعداد نتایج: 8138  

Journal: :Current Biology 2017

2013
Rachelle L. Kanippayoor Joshua H.M. Alpern Amanda J. Moehring

The production of mature and motile sperm is a detailed process that utilizes many molecular players to ensure the faithful execution of spermatogenesis. In most species that have been examined, spermatogenesis begins with a single cell that undergoes dramatic transformation, culminating with the hypercompaction of DNA into the sperm head by replacing histones with protamines. Precise execution...

Journal: :Animal reproduction science 2000
L Johnson D D Varner M E Roberts T L Smith G E Keillor W L Scrutchfield

Efficiency of spermatogenesis is the estimated number of spermatozoa produced per day per gram of testicular parenchyma. Spermatogenesis is the process of cell division and cell differentiation by which spermatozoa are produced in testes. Efficiency of spermatogenesis is influenced by species differences in the numerical density of germ cell nuclei and in the life span of these cells. Activitie...

Journal: :international journal of reproductive biomedicine 0
nasrin takzare esmaeil samizadeh saeed shoar masoumeh majidi zolbin mohammad naderan ali lashkari

background: there are numerous investigations on wide range of issues that disrupt regulatory spermatogenesis, individuals who are exposed to drug abuse faced infertility and immature spermatogenesis. objective: the aim of this study was to evaluate the addiction effects of morphine and its derivatives on rats spermatogenesis. materials and methods: 40 male wistar rats were randomly divided int...

2017
Tengfei Liu Lingling Wang Hong Chen Yufei Huang Ping Yang Nisar Ahmed Taozhi Wang Yi Liu Qiusheng Chen

Apoptosis is a tightly controlled process by which tissues eliminate unwanted cells. Spontaneous germ cell apoptosis in testis has been broadly investigated in mammals that have an associated spermatogenesis pattern. However, the mechanism of germ cell apoptosis in seasonally breeding reptiles following a dissociated spermatogenesis has remained enigmatic. In the present study, morphological ev...

Journal: :Tissue & cell 2011
I Quagio-Grassiotto R J Ortiz M H Sabaj Pérez C Oliveira

Spermatic characteristics were studied in 10 species representing several distinct groups within the catfish family Doradidae. Interestingly, different types of spermatogenesis, spermiogenesis and spermatozoa are correlated with intrafamilial groups previously proposed for Doradidae. Semi-cystic spermatogenesis, modified Type III spermiogenesis, and biflagellate sperm appear to be unique within...

Journal: :iranian journal of applied animal science 2013
a. yilmaz a. ozdal gokdal

in this review, we aim to examine the effect of extrinsic and intrinsic factors on spermatogenesis process taking into account a complex signaling pathway. primarily, it is suggested that retinoic acid (ra) has a vital function in spermatogenesis process and it is considered to be essential for completion of spermatogonia into mature spermatozoa. in the present review, the key effects of retino...

Journal: :Cancer research 1999
M L Meistrich G Wilson I Huhtaniemi

Previous studies have shown that treatment of rats with gonadotropin-releasing hormone (GnRH) analogues or steroids either before exposure to procarbazine or radiation or after irradiation enhances subsequent levels of spermatogenesis. We demonstrate here that giving a GnRH agonist after procarbazine injection also enhances spermatogenesis and fertility. We also demonstrate that GnRH agonist st...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2010
C Yan Cheng Dolores D Mruk

The physiological function of spermatogenesis in Caenorhabditis elegans, Drosophila melanogaster and mammals is to produce spermatozoa (1n, haploid) that contain only half of the genetic material of spermatogonia (2n, diploid). This half number of chromosomes from a spermatozoon will then be reconstituted to become a diploid cell upon fertilization with an egg, which is also haploid. Thus, gene...

Journal: :iranian journal of science and technology (sciences) 2005
a. amini

infertility is a relatively common problem among couples, and gossypol, a yellowishpigment detected in cottonseed, is one cause.adult nmri mice (25-35 gr) were used in this study. the animals were kept in standard conditionswith a dark and light cycle of 12:12, controlled humidity and temperature, food and water were availableadlibitium.gossypol was dissolved in ethanol and diluted by sunflower...

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