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Results 351 - 400 of 2394
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Lamanna C - - 2007
Mammalian testis contains D-aspartic acid (D-Asp), which enhances testosterone production. D-Asp, on other hand, also stimulates 17beta-estradiol synthesis in the ovary of some lower vertebrates. We studied boar testis in order to determine if D-Asp intervenes in 17beta-estradiol synthesis in the testis of those mammals which produce significant amounts of ...
Smith Carine - - 2006
The effects of exercise training on lymphocyte responses, as well as changes in circulating endocrine parameters at rest, were investigated. Seven male cyclists participated in a 4 week high-intensity (HI) cycling training intervention. Training improved performance significantly (peak power output (PPO): 1.4%, p < 0.05; 5 km time trial: 3.8%, ...
Aranha I - - 2006
Histomorphology and ultrastructure of the testis during breeding and nonbreeding phases of the reproductive cycle of the lizard Mabuya carinata are studied. Observations of the ultrastructural features of the testis during breeding and nonbreeding phases of the reproductive cycle reveal a prenuptial type of spermatogenesis and a clearcut discontinuous spermatogenic ...
Lee Young Mok - - 2006
In this study, we proposed a testis-mediated germline chimera production system based on the transplantation of testicular cells directly into heterologous testes. The testicular cells of juvenile (4-wk-old) or adult (24-wk-old) Korean Ogol chickens with a recessive pigmentation inhibitory gene, with or without prior culture, were injected (2 x 10(7) ...
Plotton Ingrid - - 2006
BACKGROUND: Sertoli cells nurse germ cells during spermatogenesis, and alterations of Sertoli cell functions have been suggested in cases of spermatogenic failures. METHODS: In this work, we measured stem cell factor (SCF) and clusterin mRNA levels, by quantitative RT-PCR, in RNA extracted from testicular biopsies of 49 azoospermic patients classified ...
Costa Deiler S - - 2007
We describe here morphological and functional analyses of the spermatogenic process in sexually mature white-lipped peccaries. Ten sexually mature male animals, weighing approximately 39 kg were studied. Characteristics investigated included the gonadosomatic index (GSI), relative frequency of stages of the cycle of seminiferous epithelium (CSE), cell populations present in the ...
Auzanneau Céline - - 2006
Sertoli cells from mammalian testis are key cells involved in the development and maintenance of stem cell spermatogonia as well as in the secretion of a Cl(-) and K(+)-rich fluid into the lumen of seminiferous tubules. The pharmacology and contribution of Cl(-) channels to the physiology of Sertoli cells were ...
Wilson Megan J - - 2006
The gene encoding the matricellular protein secreted protein, acidic and rich in cysteine (SPARC) was identified in a screen for genes expressed sex-specifically during mouse gonad development, as being strongly upregulated in the male gonad from very early in testis development. We present here a detailed analysis of SPARC gene ...
Couse John F - - 2006
The predisposition of the testis and ovary to primarily synthesize testosterone (T) and estradiol (E2), respectively, is due to gonadal-specific cell types that differentially express the various hydroxysteroid (17beta) dehydrogenase (HSD17B) isoforms. In testes, Leydig cells rely on LH stimulation to maintain expression of the type 3 (HSD17B3) isoform, which ...
Bakst M R - - 2007
Unlike mammals, there is little fundamental information about spermatogenesis in birds. This study was undertaken to clarify the morphology, histochemistry, and lectin affinity of the seminiferous epithelial cells and Leydig cells in pre-pubertal (8- to 15-week old) and adult (40- to 44-week old) domestic turkeys. In adult turkeys, three types ...
van Straaten Henny W M - - 2006
Glutamine synthetase (GS) is the only enzyme that can synthesize glutamine, but it also functions to detoxify glutamate and ammonia. Organs with high cellular concentrations of GS appear to function primarily to remove glutamate or ammonia, whereas those with a low cellular concentration appear to primarily produce glutamine. To validate ...
At-Taras Eeman E - - 2006
The abundant production of testicular estrogens and the presence of both ESR1 and ESR2 within boar testes are consistent with a role for estrogen in testicular development and/or function in this species. This study was aimed at determining the role of endogenous estrogen in the regulation of testicular development and ...
Muir Terla - - 2006
Sertoli cells are a post-mitotic terminally differentiated cell population that forms the seminiferous tubules in the adult testis and provides the microenvironment and structural support for developing germ cells. During pubertal development, Sertoli cells are responsive to follicle-stimulating hormone (FSH) to promote the expression of differentiated gene products. The basic ...
Stumpp Taiza - - 2006
Sertoli cell plays a key role in spermatogenesis. Many studies refer that this cell is not harmed by the majority of anticancer treatments known to cause damage to the testis. However, in the previous study we observed that etoposide, an efficient chemotherapeutic drug, provokes an increase in numerical density of ...
Doddamani Laxmi S - - 2006
The differentiation and development of the testis in the lizard Calotes versicolor was studied histologically and histoenzymatically from the day of oviposition (stage 27) to 2 months after hatching. The study reveals the appearance of the gonadal component as a genital ridge at stage 27. The first sign of testis ...
TIBA, Tosiro
Morphological and quantitative observations were performed on the precursor of the spermatogonial stemcell in two different generations of mink immediately before the beginning or recommencement of the breeding season, i. e. immature (7 months old) and adult (19 months old) minks. The sex cord of the immature animal has the ...
Dutta Hiran M - - 2006
The effect of endosulfan, an Organochlorine pesticide, on bluegill testes was studied. Endosulfan is aqua-toxic and has an immediate effect on fish and other aquatic life. In this experiment, we exposed the fish for 24-, 48-, 72-, 96-h, and 1- and 2-week periods. A second group of fish without exposure ...
Blottner Steffen - - 2006
Seasonal changes in spermatogenesis were studied with respect to testicular production of both testosterone and epidermal growth factor (EGF) in mink. The testes were collected in November (n = 15; testis recrudescence), February (n = 15; before breeding season), March (n = 14; breeding season), and May (n = 11; ...
Anand-Ivell Ravinder J K - - 2006
The new peptide hormone insulin-like peptide 3 (INSL3) is a member of the insulin-relaxin family, yet, unlike insulin, it signals through a new G-protein coupled receptor, LGR8, distantly related to the receptors for LH and FSH. INSL3 is produced in large amounts by the Leydig cells of the testis in ...
Tran Nicole - - 2006
Differentiation, development, and function of Leydig cells in the testis are regulated also by macrophages, vascular endothelial cells, and peritubular cells in the testis. The aim of the present study was to investigate the possible morphological substrates for communication between these cells. The cell contacts between adjacent Leydig cells, and ...
Lefevre Hervé - - 2006
BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare autosomal-dominant disorder characterized by multiple gastrointestinal hamartomatous polyps, mucocutaneous pigmentation and increased predisposition to various neoplasms. Endocrine manifestations in PJS include gynecomastia due to calcified Sertoli cell testicular tumors usually referred to as large-cell calcifying Sertoli cell tumors (LSCT). OBJECTIVE: To evaluate the ...
O'Shaughnessy P J - - 2006
The foetal Leydig cell population arises shortly after testicular differentiation at around 12.5 dpc in the mouse and 6 weeks in the human. These cells function, primarily, to produce androgens which are essential for masculinization of the foetus. The origin of the foetal Leydig cells remains uncertain but it has ...
Lamanna C - - 2006
D-aspartic acid (D-Asp), aromatase enzyme activity and the putative D-Asp involvement on aromatase induction have been studied in the testis of mature boars. The peroxidase-antiperoxidase and the indirect immunofluorescence methods, applied to cryostat and paraffin sections, were used to evaluate D-Asp and aromatase distributions. D-Asp level was dosed by an ...
Mendis-Handagama S M L C - - 2006
Anti-Mullerian hormone (AMH) produced by the immature Sertoli cells negatively regulates the postnatal Leydig cell (i.e. adult Leydig cells/ALC) differentiation, however, the mechanism is sparsely understood. AMH negatively regulates the steroidogenic function of fetal Leydig cells (FLC) and ALC. However, when this function is established in the ALC lineage and ...
Mahood I Kim IK Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, UK. - - 2006
Foetal exposure of male rats to di(n-butyl) phthalate (DBP) induces testicular changes similar to testicular dysgenesis syndrome in humans, including the formation of focal 'dysgenetic areas' within post-natal testes, surrounded by otherwise normal tubules exhibiting complete spermatogenesis. We hypothesize that these dysgenetic areas form when Sertoli (and other) cells are ...
Brehm Ralph - - 2006
During puberty, normal somatic Sertoli cells undergo dramatic morphological changes due to the differentiation of immature pre-Sertoli cells in functionally active adult Sertoli cells. Sertoli cell maturation is accompanied with loss of their mitotic activity before onset of spermatogenesis and loss of pre-pubertal and occurrence of adult immunohistochemical Sertoli cell ...
Tarulli Gerard A - - 2006
Sertoli cell number is considered to be stable and unmodifiable by hormones after puberty in mammals, although recent data using the seasonal breeding adult Djungarian hamster (Phodopus sungorus) model challenged this assertion by demonstrating a decrease in Sertoli cell number after gonadotropin depletion and a return to control levels following ...
Dahia Chitra Lekha - - 2006
Sertoli cells support the development of germ cells by providing a microenvironment in the seminiferous tubules. FSH stimulates Sertoli cell proliferation only during neonatal period till day 18 in the immature rat whereas FSH regulates only functional parameters in the adult rat Sertoli cells. This suggests that FSH exerts differential ...
Kumar Pananghat A - - 2006
Adult patients with idiopathic hypogonadotropic hypogonadism (IHH) typically present with absent puberty and therefore have prepubertal testes. IHH is recognized as one of the few curable causes of male infertility and is often effectively treated with either gonadotropins or pulsatile GnRH therapy. The objective of this study was to determine ...
Shevantaeva O N - - 2006
Parameters of spermatogenesis in male albino rats was studied after experimental acute hypobaric hypoxia. The number of spermatogenic epithelial cells, Sertoli cells, and Leydig cells in testicular tissue significantly decreased in the posthypoxic period. Single exposure to hypoxia led to significant changes in lactate concentration in the testicular tissue. Cell ...
Fujita Eriko - - 2006
RA175/TSLC1/SynCAM/IGSF4A (RA175), a member of the immunoglobulin superfamily with Ca2+-independent homophilic trans-cell adhesion activity, participates in synaptic and epithelial cell junctions. To clarify the biological function of RA175, we disrupted the mouse Igsf4a (Ra175/Tslc1/SynCam/Igsf4a Ra175) gene. Male mice lacking both alleles of Ra175 (Ra175-/-) were infertile and showed oligo-astheno-teratozoospermia; almost ...
Costa D S - - 2006
The aim of the present study was to characterize the intertubule element volume density, individual and total Leydig cells volume, Leydig cell number per testis and per gram of testis, and leydigosomatic index in adult capybaras. Eight capybaras from a commercial abattoir were utilized. The intertubular compartment volume density and ...
Petersen Cecilia - - 2006
The somatic Sertoli cell plays an essential role in embryonic determination of male somatic sex and in spermatogenesis during adult life. One individual Sertoli cell supplies a clone of developing germ cells with nutrients and growth factors and it is well established that the number of Sertoli cells present is ...
David Raymond M - - 2006
Phthalate esters containing a straight-chain backbone of 4-6 carbons have demonstrated testicular toxicity and infertility in adult and pre-adolescent rats, mice, hamsters, and ferrets. In recent years, these same phthalates have been shown to interfere with the normal development of the male reproductive tract in rodents and rabbits. The review ...
Hutson James C - - 2006
The purpose of this minireview is to present information concerning the morphologic and functional relationship between testicular macrophages and Leydig cells. Although data concerning the negative influence of macrophage-derived products on testicular Leydig cells exist, this review is focused on the stimulatory influences thought to be involved in the physiologic ...
Atanassova Nina - - 2006
Androgens are especially important for the maintenance of spermatogenesis in adulthood and the experimental withdrawal of testosterone (T) production by ethane dimenthanesulfonate (EDS) is a valuable tool for studying androgen-dependent events of spermatogenesis. The aim of the present study was to investigate the specific changes in immunoexpression of androgen receptor ...
Raeside J I JI Department of Biomedical Sciences, University of Guelph, Guelph, ON Canada N1G 2W1. - - 2006
A review of the remarkable production of steroids by the testes of the boar is presented, with the principal aims of highlighting the achievements of the Leydig cells and, at the same time, pointing to the considerable deficiencies in our understanding of its biological relevance. The onset of gonadal steroidogenesis ...
Klonisch Thomas - - 2006
In mature male seasonal breeders, the circannual cycles of testicular growth and involution involve significant changes in structure and function of both the tubular and interstitial testicular compartment. Roe deer (Capreolus capreolus) are seasonal breeders with a short defined rutting season from mid-July to mid-August and represent a unique non-rodent ...
Zhang Xue-Sen - - 2006
Sertoli cells play a key role in triggering and regulating the process of spermatogenesis. Failure of a Sertoli cell to mature functionally will presumably render it incapable of supporting germ cell survival and development that appeared after puberty. Expression of cytokeratin 18 (ck-18) intermediate filaments indicates a state of undifferentiation ...
Moundipa Paul F - - 2005
AIM: To determine the androgenic effects of Basella alba and Hibiscus macranthus extracts in the rat and the bull, and to develop a novel in vitro test system using Leydig cells from bull testes. METHODS: The effect of methanol extracts from both plants on testosterone production in isolated Leydig cells ...
Abd-Elmaksoud Ahmed - - 2005
Several fibroblast growth factors (FGFs) are implicated in proliferation and differentiation of both somatic and germ cells during testicular development, as well as in spermatogenesis of adult testis. The expression of FGF2 was studied in the adult bovine testis using quantitative RT-PCR, RNA in situ hybridization, and immunohistochemistry. Quantitative RT-PCR ...
O'Shaughnessy P J - - 2005
During development in the mouse, two populations of Leydig cells arise sequentially. The fetal Leydig cell population arises shortly after testicular differentiation and functions primarily to produce androgens that are essential for masculinization of the fetus. The origin of the fetal Leydig stem cells remains uncertain, but it has been ...
Fujino Ryu-Suke - - 2006
In spermatogenesis, Sertoli cells serve as supporting cells for the proliferation and differentiation of germ cells. However, it appears that Sertoli cell function is regulated by adjacent spermatogonial cells in the testis because expression of lipocalin-2 mRNA, which encodes an iron-siderophore-binding protein, is barely detectable in Sertoli cells of germ ...
Sarraj M A - - 2005
In an effort to understand the mechanisms that underpin gonadal differentiation at the time of sex determination, we identified a cDNA encoding a putative novel testis expressed scavenger receptor, Tesr. Based on its domain structure, we hypothesize that the function of Tesr is similar to that of other scavenger receptors ...
Myers M - - 2005
Testes of hypogonadal (hpg) mice show arrested postnatal development due to congenital deficiencies of gonadotrophin-releasing hormone (GnRH) and gonadotrophin synthesis and secretion. Follicle-stimulating hormone (FSH), androgen or oestrogen treatment restore qualitatively normal spermatogenesis in hpg testes. Understanding the cellular and molecular changes accompanying hormone-induced spermatogenesis in hpg mice requires detailed ...
Leal Marcelo C - - 2006
Marmosets are New World small primates phylogenetically close to humans and are commonly used in biomedical research. Although the reproductive biology of the common marmoset Callithrix jacchus is fairly well investigated, there are few data available for testis function for its close relative, Callithrix penicillata. In this regard, the present ...
Devkota Bhuminand - - 2006
The present study demonstrates the postnatal developmental changes in immunohistochemical localization of alpha-smooth muscle actin (SMA) and vimentin in the bovine testis. In the peritubular myoid cells of seminiferous tubules and the sub-epithelial and stromal cells of straight tubules and the rete testis, alpha-SMA starts appearing at around 4 months ...
Ojha Priti - - 2006
OBJECTIVE: To examine the role of Sertoli cells in the antispermatogenic action of two nonsteroidal male contraceptive compounds (CDRI-84/35 and gossypol) by evaluating their effect on some key parameters of Sertoli cell function in vitro. METHODS: Primary cultures of Sertoli cell were established from 18-day-old rat testis and treated on ...
De Gendt, Karel
Androgens play a pivotal role in the control of spermatogenesis, but the cellular and molecular mechanisms by which they affect germ cell development remain poorly understood. Since germ cells themselves do not express a functional androgen receptor(AR), androgen regulation of spermatogenesis is thought to be mediated by somatic cells such ...
Meng Jing - - 2005
Within the mammalian testis, specialized tight junctions between somatic Sertoli cells create basal and apical polarity within the cells, restrict movement of molecules between cells, and separate the seminiferous epithelium into basal and adluminal compartments. These tight junctions form the basis of the blood-testis barrier, a structure whose function and ...
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