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Results 501 - 550 of 2394
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Stoltenberg Meredin - - 2004
Recent studies suggest that bismuth accumulates in Leydig cells. In addition, a reduced level of serum testosterone and a statistically significant reduction of Leydig cells have been observed. It was therefore hypothesized that Bi has a direct toxic effect on rat Leydig cells. We have now developed a method for ...
Osada Makoto - - 2004
Aromatase activities and estrogen contents in the gonad of Japanese scallop, Patinopecten yessoensis, were determined during gonadal development and estrogenic cells in the testis were identified immunohistochemically. Ovaries and testes developed rapidly during January and February to reach the mature stage in March and the spawning stage in April. Increases ...
Willerton Louise - - 2004
Proliferation and cord formation by embryonic Sertoli cells are pivotal events involved in testis morphogenesis. A number of growth factors have been implicated in mediating these events. However, the exact level of involvement and importance of each as yet remains elusive. We have adopted an in vitro approach to assess ...
Holt W V - - 2004
Testicular development in the harbour porpoise Phocoena phocoena was examined using animals (n = 192) stranded or by-caught off the coast of England, Wales and Scotland. Classification of animals according to their stage of sexual development was undertaken using gonadal morphology and the distribution of cytoskeletal proteins. Smooth muscle actin ...
Wootton Laura L - - 2004
The distribution of the secretory pathway Ca2+ -ATPase (SPCA1) was investigated at both the mRNA and protein level in a variety of tissues. The mRNA and the protein for SPCA1 were relatively abundant in rat brain, testis and testicular derived cells (myoid cells, germ cells, primary Sertoli cells and TM4 ...
Lucas Thaís F G - - 2004
The aim of the present work was to study the effect of muscarinic agonist on cell proliferation and muscarinic acetylcholine receptors (mAChRs) regulation in rat Sertoli cells. Primary cultures of Sertoli cells were obtained from 8-day and 15-day old male Wistar rats. In proliferation assays, [methyl-3H]thymidine incorporation in Sertoli cells ...
O'Connor Anne E - - 2004
Inhibin is a dimeric glycoprotein that suppresses follicle-stimulating hormone (FSH) secretion from the pituitary. Two bioactive forms of inhibin exist, inhibin A and B. The availability of specific immunoassays for each of the isoforms has enabled the study of the individual inhibins and their physiological roles. In the male, inhibin ...
Zhang Zhi-Hong - - 2004
Cytoskeletons in Sertoli cell play an important role in process of spermatogenesis. The expression and distribution of the intermediate filaments, vimentin, keratin and desmin, were studied in the Sertoli cells of the cryptorchid testis of rhesus monkey. Vimentin was localized in the perinuclear region of Sertoli cells of the normal ...
Lo Nostro Fabiana L - - 2004
The swamp eel, Synbranchus marmoratus, is a freshwater protogynic diandric species. Primary males develop directly as males while secondary males arise from the sex reversal of females. Fishes from Argentine and Brazil inland waters were collected, examined and compared for this study. In order to characterize the interstitial testicular compartment, ...
Chung Sanny S W SS Department of Genetics and Development, Columbia University College of Physicians and Surgeons, New York, New York 10032, - - 2004
Targeted mutagenesis of the retinoic acid receptor alpha (RAR alpha) gene has revealed its essential role in spermatogenesis. Although cells in all stages of spermatogenesis were detected in RAR alpha(-/-) testes, there was an increase in degenerating pachytene spermatocytes and a temporary developmental arrest in step 8-9 spermatids in the ...
Lei Z M - - 2004
The LH receptor knockout model, developed in our laboratory, was used in determining what FSH alone can do in the absence of LH signaling and whether any of the testicular LH actions are not mediated by androgens. The results revealed that null animals contained smaller seminiferous tubules, which contained the ...
Ahtiainen Maarit - - 2004
In the present study, we describe a novel mouse model for inducible germ cell ablation. The mice express herpes simplex virus thymidine kinase (HSV-TK) under the inhibin-alpha subunit promoter (Inhalpha). When adult transgenic (TG) mice were treated with famciclovir (FCV) for 4 wk, their spermatogenesis was totally abolished, with only ...
Gye M C - - 2004
C-terminal Src Kinase (Csk) is a cytoplasmic tyrosine kinase that phosphorylates a critical tyrosine residue in each of the Src family kinases to inhibit their activities. To investigate the possible regulation of spermatogenesis by Src-Csk loop, the postnatal changes in the expression of Csk were examined in mouse testes. Semiquantitative ...
Mendis-Handagama S M L C - - 2004
Thyroid hormones (TH) stimulate oxidative metabolism in many tissues in the body, but testis is not one of them. Therefore, in this sense, testis is not considered as a target organ for TH. However, recent findings clearly show that TH have significant functions on the testis in general, and Leydig ...
Douglas Gabrielle C - - 2004
The metallopeptidase angiotensin-converting enzyme (ACE) plays a pivotal role in the cardiovascular system by generating the vasoconstrictor peptide angiotensin II. A homolog of ACE with different substrate specificity, ACE2, has recently been cloned that shows an expression pattern restricted to endothelial cells of the heart and kidney, epithelial cells of ...
Chen Haolin - - 2004
The wealth of knowledge about the function and regulation of adult Leydig cells, the cells within the mammalian testis that produce testosterone, make these cells ideal for studying principles and mechanisms of aging. A hallmark of mammalian aging is decreased serum testosterone concentration. In the Brown Norway rat, this has ...
Hermo Louis - - 2004
Aquaporins (AQPs) are transmembrane protein channels that allow the rapid passage of water across an epithelium at a low energy requirement, though some also transport glycerol, urea, and solutes of various sizes. At present, 11 members of the AQP family of proteins have been described in mammals, with several being ...
Neubauer Katrin - - 2004
Teratozoospermia (ejaculation of <40% morphologically normal sperm) commonly occurs within the Felidae, including certain domestic cats, but the cellular and molecular mechanisms that give rise to this phenomenon remain unknown. This study quantified spermatogenesis to identify differential dysfunctions in teratospermic versus normospermic (>60% normal sperm/ejaculate) domestic cats. Sperm used were ...
Schmahl Jennifer - - 2004
Recently, we demonstrated that loss of Fgf9 results in a block of testis development and a male to female sex-reversed phenotype; however, the function of Fgf9 in sex determination was unknown. We now show that Fgf9 is necessary for two steps of testis development just downstream of the male sex-determining ...
Hill Christine M - - 2004
In the rat, quantitatively normal spermatogenesis is maintained only when intratesticular testosterone (ITT) levels greatly exceed the peripheral T concentration. When ITT concentrations fall below a threshold, germ cells are lost at specific stages of the seminiferous cycle. Germ cells can be restored by high doses of T that binds ...
Lee Nikki P Y - - 2004
The seminiferous tubule of the mammalian testis is largely composed of Sertoli and germ cells, which coordinate with Leydig cells in the interstitium and perform two major physiological functions, namely spermatogenesis and steroidogenesis respectively. Each tubule is morphologically divided into (i) the seminiferous epithelium composing Sertoli and germ cells, and ...
Nakagawa Akihisa - - 2004
Class B scavenger receptor type I (SR-BI), a multiligand membrane protein, exists in various organs and cell types. In the testis, SR-BI is expressed in two somatic cell types: Leydig cells and Sertoli cells. Unlike interstitially localized Leydig cells, Sertoli cells present within the seminiferous tubules keep contact with spermatogenic ...
Zhang Yuan-Qiang - - 2004
AIM: To investigate the stage-specific localization of transforming growth factor (TGF) beta1 and beta3 during spermatogenesis in adult human testis. METHODS: The localization of TGFbeta1 and beta3 was investigated by immunohistochemical staining method employing specific polyclonal antibodies. RESULTS: Both TGFbeta1 and beta3 and their receptors were preponderant in the Leydig ...
Lee Do-Youn - - 2004
BPA, bisphenol A, a monomer of epoxy resins and polycarbonate plastic, is used in many consumer products including the plastic linings of cans for food and babies' bottles. BPA has been reported to cause reproductive toxicity and affects cells in rats and mice at high doses. In this study, the ...
Hombach-Klonisch Sabine - - 2004
Roe deer are seasonal breeders and show cyclic variation in testicular volume and cellular differentiation within the tubular and interstitial testis compartment. We have employed the roe deer as a model to elucidate the expression of the postpubertal Leydig cell marker INSL3 during seasonal changes in Leydig cell differentiation. Roe ...
Lobo Maria V T - - 2004
The intermediate filament protein nestin is predominantly expressed in some stem/progenitor cells and appears to be a useful molecular tool to characterise tumours originating from precursor cells of neuroectodermal and mesenchymal lineages. Leydig cells originate in the adult testis by differentiation from stem cells and express a variety of neural ...
Wellejus Anja - - 2004
17 alpha-Ethinylestradiol (EE) can induce oxidative DNA damage in terms of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in rat testicular cells by an apparent estrogen receptor-mediated mechanism. We investigated differential susceptibility to EE in cell sub-populations from rat testes and the role of rat 8-oxo-guanine DNA glycosylase (rOGG1). Isolated rat testicular cells were incubated ...
Gye M C - - 2004
The cathepsin family of proteolytic enzymes play an important role in the remodeling seminiferous epithelia in rodent testis. In an effort to uncover the cathepsin L expression in diverse pathological conditions in human testis, the immunohistochemical localization of cathepsin L was conducted in human testis under diverse male infertility condition ...
Schön J - - 2004
Seasonally regulated breeding in roe deer, Capreolus capreolus, is associated with significant changes in testis mass, structure and function. This study has quantified seasonal changes of morphometric parameters and cellular composition in roe deer testis parenchyma. Tissue samples were collected bimonthly during a complete annual cycle. Morphometric parameters of seminiferous ...
Rommerts F F G - - 2004
The mechanism by which ethane 1,2-dimethanesulfonate (EDS) selectively kills Leydig cells is poorly understood. To characterize further the cell-specific actions of EDS, we studied biochemical and morphological changes during apoptosis in different Leydig cell and non-steroidogenic cell models. Rat testicular and H540 tumor Leydig cells were killed by 1-2 mM ...
Gheri Gherardo - - 2004
The present investigation has been performed to obtain a complete distributional map of the oligosaccharidic component of the glycoconjugates in the testis of the human newborn. For this purpose seven eight HRP-conjugated lectins (SBA, DBA, PNA, WGA, OOA, UEAI, LTA and ConA) along with enzymatic treatments, were used. The Sertoli ...
Khan U W - - 2004
The present study was aimed at investigating ultrastructure of different testicular cells and their interactions through various junctional specializations during different phases of reproductive cycle in wall lizard H. flaviviridis to develop an integrated approach of cell-cell interaction in control of testicular functions. Specialized steroid synthesizing cell organelles such as ...
Ha Tae-young - - 2004
The expression of three isoforms of nitric oxide synthase (NOS) were examined in the testis and epididymis of a thoroughbred horse. Immunohistochemical studies demonstrated the presence of eNOS immunostaining in some germ cells in the seminiferous tubules and in vascular endothelial cells in the interstitial tissues. Interstitial cells, most likely ...
Khan U W - - 2004
The present in vitro Sertoli cell-enriched culture study was aimed to understand the precise role of FSH and testosterone either alone or in combination in regulation of Sertoli cell nursing function such as lactate production, which in turn is utilized by the germ cells as an energy substrate. The stimulatory ...
Gheri Gherardo - - 2004
The saccharidic content of the glycoconjugates has been studied in the descended the undescended testes of a 8 years old boy. For this purpose, a battery of seven HRP-conjugated lectins (SBA, DBA,PNA,WGA,UEAI, LTA and ConA) was used. D-galactose-N-acetyl-D-galactosamine and alpha-L-fucose sugar residues, which were present in the cytoplasm of the ...
Selva David M - - 2004
The liver X receptor/retinoid X receptor (LXR/RXR)-regulated gene ABCA1 effluxes cellular cholesterol and phospholipid to apolipoprotein A1 (apoA1), which is the rate-limiting step in high-density lipoprotein synthesis. The RXR pathway plays a critical role in testicular lipid trafficking, and RXRbeta-deficient male mice are sterile and accumulate lipids in Sertoli cells. ...
Grover Amit - - 2004
Follicle stimulating hormone (FSH) plays important roles during testicular development and in the maintenance of spermatogenesis in the adult. However, the cellular events or pathways that FSH regulates to achieve these effects in Sertoli cells, where the FSH receptors (FSH-R) are located, is still not fully elucidated. The development of ...
Zhu Qianlong - - 2004
Within seminiferous tubules, Sertoli cells form three types of actin-filament-containing cell junctions, viz., tight junctions, ectoplasmic specializations, and tubulobulbar complexes. These Sertoli cell junctions are involved in the formation of the blood-testis barrier, germ cell translocation, and the release of spermatozoa. Actin and actin-binding proteins are important for these functions. ...
Weber Lynn P - - 2004
Sublethal effects observed in fish exposed to environmental estrogens may be mediated via stimulation of cell death. To investigate whether cell death is induced in fish after chronic exposure to estrogenic chemicals, Japanese medaka (Oryzias latipes) were exposed from hatch until sexual maturity to 10 ng/L 17alpha-ethinylestradiol (EE2) or acetone ...
Svechnikov K - - 2004
Interleukin-1alpha (IL-1alpha) plays an important role(s) in the regulation of immune and inflammatory responses. The testis is an immunologically privileged organ and the variety of effects exerted by IL-1alpha on this organ have yet to be explored in detail. The aim of the present review is to describe our current ...
Suzuki Hiroetsu - - 2004
The hypogonadic rat is characterized by male sterility, reduced female fertility, and renal hypoplasia controlled by a single recessive allele (hgn) on chromosome 10. Plasma testosterone is low and levels of gonadotropins are high in adult male hgn/hgn rats, indicating that the cause of hypogonadism lies within the testis itself. ...
Imai T - - 2004
In the mammalian postnatal testis, the biochemical and structural features of Sertoli cells change, depending on developmental stage and spermatogenic cycle, to support efficient spermatogenesis. Consequently, basic transcription factors that determine fundamental properties should be strictly maintained in postnatal Sertoli cells. We have confirmed that GATA-4 expression is kept at ...
Kotula-Balak Małgorzata - - 2004
Aromatization of androgens into estrogens is catalyzed by a microsomal enzyme, P450 aromatase. Males of the mouse strain B10.BR and its congenic mutant strain B10.BR-Ydel (with a partial deletion in the long arm of the Y chromosome) were used to identify the cellular source of estrogens within the testis. Immunocytochemistry ...
Tong M H - - 2004
Estrogen sulfotransferase (EST) is a cytosolic enzyme that catalyzes the sulfoconjugation and inactivation of estrogens. It is expressed abundantly in the mammalian testes in which it may modulate the activity of locally produced estrogen. We demonstrate here that testicular Leydig cells from mice rendered deficient in EST expression by targeted ...
O.A. Al-Dokhi
The histomorphological as well as the ultrastructural features of the testicular tissue of the snake <I>Eryx jayakari</I> (<I>E. jayakari</I>) were described. Also, the spermatogenic cells, including spermatogonia and primary and secondary spematocytes were illustrated. The non-spermatogenic cells represented by the Sertoli cells were also demonstrated. The interstitial tissue, most importantly ...
Nakanishi Yoshinobu - - 2004
More than half of differentiating spermatogenic cells undergo apoptosis before maturing into spermatozoa during mammalian spermatogenesis. These cells are selectively and rapidly eliminated through phagocytosis by Sertoli cells, a testicular somatic cell type possessing phagocytic activity. We have investigated the mechanism by which Sertoli cells specifically recognize and phagocytose apoptotic ...
Holdcraft Robert W - - 2004
Androgen receptor function is required for male embryonic sexual differentiation, pubertal development and the regulation of spermatogenesis in mammals. During spermatogenesis, this requirement is thought to be mediated by Sertoli cells and its genetic and pharmacological disruption is manifested in spermatocytes as meiotic arrest. Through studies of a hypomorphic and ...
Chaves-Pozo Elena - - 2004
The gilthead seabream is a protandrous seasonal breeding teleost that is an excellent model for studying the testicular regression process which occurs in both seasonal testicular involution and sex reversion. Little is known about the cell types and the molecular mechanisms involved in such processes, mainly because of the lack ...
Hermo Louis - - 2004
beta-Hexosaminidase (Hex) catalyzes the hydrolysis of terminal sugar residues from a number of substrates such as GM2 gangliosides, glycoproteins, glycolipids, and glycosaminoglycans. As an enzyme present in lysosomes of epithelial cells of the adult rat epididymis, it serves to degrade substances endocytosed from the epididymal lumen. In this way, it ...
Kotula-Balak Małgorzata - - 2004
Klinefelter's syndrome (47, XXY) is the most common chromosome aneuploidy in men and is usually characterized by underdeveloped testes and sterility. The aim of the present study was to detect cellular distribution of androgen receptors (AR) and aromatase in testes of patient with KS. The tissue sections were processed for ...
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