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Male Gonads (male + gonad)
Selected AbstractsOntogeny of the androgen receptor expression in the fetal and postnatal testis: Its relevance on Sertoli cell maturation and the onset of adult spermatogenesisMICROSCOPY RESEARCH AND TECHNIQUE, Issue 11 2009Rodolfo A. Rey Abstract From fetal life to adulthood, the testis evolves through maturational phases showing specific morphologic and functional features in its different compartments. The seminiferous cords contain Sertoli and germ cells, surrounded by peritubular cells, and the interstitial tissue contains Leydig cells and connective tissue. Sertoli cells secrete anti-Müllerian hormone (AMH), whereas Leydig cells secrete androgens. In the fetal and early postnatal testis, Leydig cells actively secrete androgens. Sertoli cells are morphologically and functionally immature,e.g., they secrete high levels of AMH,and germ cells proliferate by mitosis but do not enter meiosis. During infancy and childhood, Leydig cells regress and testosterone secretion declines dramatically. Sertoli cells remain immature and spermatogenesis is arrested at the premeiotic stage. At puberty, Leydig cells differentiate again, and testosterone concentration increases and provokes Sertoli cell maturation,e.g., down-regulation of AMH expression,and germ cells undergo meiosis, the hallmark of adult spermatogenesis driving to sperm production. An intriguing feature of testicular development is that, although testosterone production is as active in the fetal and early postnatal periods as in puberty, Sertoli cells and spermatogenesis remain immature until pubertal onset. Here, we review the ontogeny of the androgen receptor expression in the testis and its impact on Sertoli cell maturation and the onset of pubertal spermatogenesis. We show that the absence of androgen receptor expression in Sertoli cells underlies a physiological stage of androgen insensitivity within the male gonad in the fetal and early postnatal periods. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc. [source] The matricellular protein SPARC is internalized in Sertoli, Leydig, and germ cells during testis differentiationMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 5 2006Megan J. Wilson Abstract 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 and protein expression during testis development, from 11.5 to 15.5 days post coitum (dpc). Section in situ hybridization analysis revealed that SPARC mRNA is expressed by the Sertoli cells in the testis cords and the fetal Leydig cells, found within the interstitial space between the testis cords. Immunodetection with anti-SPARC antibody showed that the protein was located inside the testis cords, within the cytoplasm of Sertoli and germ cells. In the interstitium, SPARC was present intracellularly within the Leydig cells. The internalization of SPARC in Sertoli, Leydig, and germ cells suggests that it plays an intracellular regulatory role in these cell types during fetal testis development. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Immunoexpression of Aromatase in Immature and Adult Males of the European Bison (Bison bonasus, Linnaeus 1758)REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2010I Kopera Contents Based on recent literature dealing with the role of oestrogens in the male gonad, attempts were undertaken to reveal the site of aromatization within the testis of the European bison (Bison bonasus). Testes were collected from culled animals living in free-ranging populations in Bialowieza Forest, Poland (nine males aged 8 months to 10 years). Moreover, to check for any alterations in the expression of testicular aromatase between American bison (Bison bison) and European bison, testes from one adult 10-year-old individual were also chosen for this study. For immunohistochemistry, 4% formaldehyde fixative was used. Both qualitative and quantitative evaluations of immunohistochemical staining were performed. Leydig cells, Sertoli cells and germ cells exhibited a positive immunoreaction for aromatase in testes of immature and sexually mature bison. A marked increase in aromatase expression was observed in three adult European individuals with impaired spermatogenesis. Consistent with recent data and those of our own, it might be suggested that the strong expression of aromatase negatively affects spermatogenic function in bison testes and may serve as a possible explanation of specific sperm defects observed in European bison bulls. On the contrary, one cannot exclude that differences in the aromatase immunoexpression levels are attributed to the homozygosity, the cause of frequent disease in European bison. [source] Prenatal development of murine gonads with special reference to germ cell differentiation: a morphological and immunohistochemical studyANDROLOGIA, Issue 3 2007A. E. Zayed Summary The prenatal differentiation of male and female gonads of the mouse was investigated both morphologically and immunohistochemically. Sexual dimorphism could be detected as early as 12 days post-coitum (dpc) by the appearance of the primary elements of the tunica albuginea and positive immunoreactivity for anti-Muellerian hormone in the Sertoli cells of the male gonad. Male germ cells passed two waves of mitotic activity, a first wave between 12 and 14 dpc, which is followed by apoptosis of the old germ cell generation, and a second wave between 17 and 20 dpc. Oct-4 was expressed as a juxtanuclear ring in the cytoplasm of germ cells up to 17 dpc. Subsequently, it was down-regulated and completely disappeared in 20 dpc full-term fetuses. By contrast, M2A antigen revealed only a weak immunoreaction in some germ cells of 14 dpc gonads, but exhibited strong signals in all germ cells of 20 dpc full-term fetuses. Therefore, we postulate that, in the mouse, prenatal germ cells represent two populations: the first is immunopositive for Oct-4 and disappeared in full-term fetuses, whereas the second appeared in 14 dpc and is immunopositive for M2A antigen. [source] Advanced fluorescence in situ hybridization to localize and quantify gene expression in Japanese medaka (Oryzias latipes) exposed to endocrine-disrupting compoundsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2009June-Woo Park Abstract In an earlier study, we described the development of fluorescence in situ hybridization (FISH) using confocal microscopy to localize and quantify gene expression in fish. Here, we report the results of FISH application to investigate effects of model endocrine-disrupting chemicals (EDCs), 17,-ethinylestradiol (EE2) and 17,-trenbolone (TB), on expressions of EDC-responsive genes in Japanese medaka (Oryzias latipes) at the cellular/tissue level paired with histological observation. Gene expressions of vitellogenin-II (Vit-II), androgen receptor (AR), and cytochrome P450 gonadal aromatase (CYP19a) were determined after exposure to 5, 50, or 500 ng/L of EE2 or 50, 500, or 5,000 ng/L of TB for 7 d. Exposure to the greatest concentration of EE2 or TB significantly reduced fecundity and caused histological alterations in gonads. 17,-Ethinylestradiol induced Vit-II expression in both male gonads and liver relative to controls and resulted in greater intensity of hematoxylin staining in hepatocytes, which was significantly correlated with Vit-II induction in liver. When exposed to EE2 at less than 50 ng/L, CYP19a expression associated with early stage oocytes was greater than that in controls. However, at 500 ng/L, this trend was reversed. The greater Vit-II expression in testis from all EE2 groups, and the lesser expression of CYP19a in ovaries from the 500 ng/L group, likely is related to changes in the number of cells in which these genes are predominantly expressed rather than to an increase in expression per cell. 17,-Trenbolone significantly induced AR expression in ovaries but did not alter AR expression in female liver. It was concluded that FISH combined with histology enables advanced elucidation of molecular effects of chemicals by associating changes in gene expression with certain tissues and/or cell types and allows these changes to be related to histological effects. [source] Leptin and leptin receptor in human seminal plasma and in human spermatozoaINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2003T. Jope Summary Leptin, a 167 amino acid peptide, is known to influence the gonads via direct and indirect effects. Recent studies provide contradictory proposition about the peripheral impact of leptin in the male gonads. Thus, we examined leptin and its receptors in human seminal plasma and in human ejaculated spermatozoa by Western blot technique and fluorescence microscopy. In seminal plasma we found a free leptin band (16 kDa) by an anti-leptin polyclonal antibody. Incubation of seminal plasma with recombinant leptin caused a statistically significant increase in the amount of free leptin (p < 0.01) and supports this finding. Furthermore, a soluble leptin receptor (145 kDa) was found in human seminal plasma in the same specimen. We also detected a 145-kDa leptin receptor isoform in ejaculated spermatozoa as a possible target of leptin action in the male genital tract, which was localized at the tail of spermatozoa by immunofluorescence microscopy only. This receptor was significantly associated with the intactness of sperm plasma membranes. Spermatozoa with deteriorated membranes contained 49.2 ± 6.9% leptin receptor signal intensity compared with spermatozoa having intact membranes (p < 0.01). This finding is difficult to interpret and may be caused by a leakage of OB-R due to loss of membrane integrity. In conclusion, these data provide further hints for a peripheral role of leptin in the male genital tract, possibly, by an interaction between leptin and spermatozoa via sperm leptin receptors. [source] Anatomy and ultrastructure of the reproductive organs in Dactylopodola typhle (Gastrotricha: Macrodasyida) and their possible functions in sperm transferINVERTEBRATE BIOLOGY, Issue 1 2008Alexander Kieneke Abstract. The reproductive anatomy of gastrotrichs is well known for several species, especially for the marine taxon Macrodasyida. However, there is little information on the reproductive organs and the modes of mating and sperm transfer in putative basal taxa, which is necessary for accurate reconstruction of the ground pattern of the Gastrotricha. We present the first detailed morphological investigation of the reproductive system of a putative basal gastrotrich, Dactylopodola typhle, using transmission and scanning electron microscopy, histology, and microscopic observations of living specimens. Dactylopodola typhle is a hermaphrodite that possesses paired female and male gonads, an unpaired uterus with an outlet channel that we call the cervix, and an additional accessory reproductive organ, the so-called caudal organ. We hypothesize that the hollow, secretory caudal organ serves for picking up autospermatozoa (self-sperm), for spermatophore formation, and finally for transferring the autospermatophore to a mating partner. The allospermatophore (foreign spermatophore) is stored within the uterus where fertilization occurs. We think that the mature and fertilized egg is released through the cervix and the dorsolateral female gonopore, and not by rupture of the body wall. Based on the morphology, we provide a plausible hypothesis for spermatophore formation and transfer in D. typhle. Preliminary phylogenetic considerations indicate that the stem species of Macrodasyida, perhaps that of all Gastrotricha, had paired ovaries and paired testes, an unpaired uterus, and only one accessory reproductive organ. [source] Reproductive cycle and sex inversion in razor fish, a protogynous labrid in the southern Mediterranean SeaJOURNAL OF FISH BIOLOGY, Issue 6 2004G. Candi The reproductive biology of the Mediterranean razor fish Xyrichthys novacula was investigated by demographic data and histological analysis of the female, intersexual and male gonads. Specimens were collected by bottom trawl on a monthly basis between June 2000 and July 2001 in a sandy bay in southern Thyrrenian. Gonad histology confirmed that the Mediterranean razor fish is a monandric, protogynous hermaphrodite. Females reached first sexual maturity at 100 mm (LT) and the estimated mean LT at first maturity (L50) was 125 mm. Females exhibited asynchronous ovarian development and multiple ovulations occurred over the spawning period. Vitellogenesis started in early May and spawning occurred from late May until late September. Sexual transition involved a large-scale atresia of all oocyte stages and a massive degeneration of ovarian tissue followed by primordial germ cells proliferation. Sex change began at spawning time (June) but transitional individuals tended to cluster at the end of the reproductive period (September). They accounted for 17·1% of the population sampled and were found in a broad size range (105,150 mm LT). [source] Comparative morphology of male reproductive systems in Mediterranean blennies (Blenniidae)JOURNAL OF FISH BIOLOGY, Issue 1 2000U. Richtarski The male reproductive organs of 16 species of Mediterranean Blenniidae (Aidablennius sphynx, Blennius ocellaris, Coryphoblennius galerita, Lipophrys adriaticus, L. canevae, L. dalmatinus, L. nigriceps, Parablennius gattorugine, P. incognitus, P. sanguinolentus, P. rouxi, P. tentacularis, P. zvonimiri, Paralipophrys trigloides, Salaria pavo and Scartella cristata) consist of pairs of testes, testicular glands, spermatic ducts, and blind pouches. Three main types of accessory sex organs were found by comparing the external morphology of the male gonads. Differences between species were observed in the volume of the testicular gland in relation to the volume of the testis and in the size and length of the spermatic ducts, and blind pouches. The anatomy of the testicular glands of all species investigated do not differ. Each gland consists of ducts that appear to be tubules which terminate at the testis periphery on one side and at the spermatic duct on the other side. Contrary to previous claims, A. sphynx has no fat body in place of the testicular gland; the gland of this species was not distinguishable from that of the other species investigated. In the Lipophrys species, in P. trigloides, and in B. ocellaris, a transition zone between testis and testicular gland is present. The testicular blind pouches empty into the spermatic ducts, into the ureter, or separately on the genital papilla. In most species, the epithelium has no or low folds, while in S. pavo it possesses high folds that nearly fill the lumen of the blind pouches. The morphological results are discussed in connection with taxonomy, ecology, and behaviour of the fishes. [source] | |||||||||||||