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At least 1,171 records · Page 65Linked to original sources
PubMed2003

Triiodothyronine decreases the activity of the proximal promoter (PII) of the aromatase gene in the mouse Sertoli cell line, TM4.

Estrogens and thyroid hormones play a significant role in regulating functions and development of the testis. The synthesis of estrogens from androgens is catalyzed by the enzyme complex termed aromatase, which in the testis displays an age-related cellular compartmentalization, primarily in Sertoli cells in immature animals, whereas in adults it is expressed in Leydig and germ cells. T3 induces a precocious terminal differentiation of prepubertal Sertoli cells together with a dramatic decrease of their aromatase activity. In the present work, we have examined the mechanism by which T3 exerts this inhibitory action on aromatase expression. As an experimental model, we used the mouse Sertoli cell line TM4, which conserves a large spectrum of functional features present in immature Sertoli cells. For instance, after revealing the presence of aromatase by immunocytochemistry and measuring its enzymatic activity, we confirmed in this cell line the functional events previously characterized in primary cultures of immature rat Sertoli cells: 1) a strong stimulation of aromatase activity by dibutyryl-cAMP [(Bu)2cAMP] (simulating FSH action); and 2) the inhibition of aromatase activity by incubation with T3 under basal condition and after (Bu)2cAMP stimulation. After identifying promoter II as the regulatory region located immediately upstream of the transcriptional initiation site in the TM4 cell line by rapid amplification of cDNA ends analysis, we conducted experiments to examine the molecular mechanism by which thyroid hormones modulate aromatase gene expression in this cell line. TM4 cells were transfected with plasmids containing different segments of the rat promoter II sequence ligated to a luciferase reporter gene. Analysis of the activities of these promoter fusions demonstrated that T3 inhibits basal and (Bu)2cAMP-stimulated activity of the aromatase promoter. This effect was not revealed in T3-treated cells transfected with construct in which the steroidogenic factor-1 (SF-1) response element was mutated. These results indicate that the inhibitory effect of T3 requires the integrity of the SF-1 response element and are further supported in the EMSA. The EMSA experiments demonstrated that thyroid hormone/thyroid receptor alpha1 complex (TH/TRalpha1) is able to compete with SF-1 in binding to oligonucleotides containing an SF-1 motif, an element essential for the activity of the PII aromatase promoter. The findings suggest that the binding of the thyroid hormone/thyroid receptor alpha1 complex to the SF-1 motif is the molecular mechanism by which T3 exerts an inhibitory effect on aromatase gene expression in the TM4 cell line.

Animals↗
PubMed1991

Histological observations of the reproductive organs of the male dog from birth to sexual maturity.

Development of the testis, epididymis and prostate in 53 male beagles was examined histologically with PAS-hematoxylin stain from birth to sexual maturity. The diameter of the seminiferous tubules of the testes was less than 100 microns until 20 weeks of age, however, it increased markedly between 22 and 28 week of age, reaching 180 +/- 7 (mean +/- SD) microns at 28 weeks of age. Only Sertoli cells and gonocytes (or spermatogonia) were detected in the seminiferous tubules until 16 weeks of age. Spermatocytes and spermatids appeared in the tubules at 20 and 22 weeks of age, respectively. Spermatozoa were first observed in the testes of 2 of the 5 dogs at 26 weeks of age and were found in the testes of all the 3 dogs at 28 weeks of age. The diameter of the ducts in the cauda epididymidis was 146 +/- 4 microns at 20 weeks of age. Thereafter it increased markedly, reaching 341 +/- 14 microns at 28 weeks of age. The height of the epithelium and stereocilia in the ducts of the caput epididymidis increased markedly at about 28 weeks of age. A large number of spermatozoa was seen in the lumens of the ducts of the corpus and cauda epididymidis after 32 weeks of age. The shape of the lumens in the glandular alveoli of the prostate became irregular as a result of projection of the glandular epithelium into the enlarged lumens and the epithelial cells of the alveoli became PAS-positive at 24 weeks of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Noncovalent binding of poly(ADP-ribose) to nuclear matrix proteins: developmental changes and tissue specificity.

Poly(ADP-ribose) is a nuclear polynucleotide involved in the regulation of chromatin functions via covalent and/or noncovalent modification of nuclear proteins. Using a binding assay on protein blots, we searched for poly(ADP-ribose) binding proteins in nuclear matrices from testes of differently aged rats as well as from various adult rat tissues (brain, liver, spleen). We found that nuclear matrix proteins represent a significant subset of the nuclear proteins that can establish noncovalent interactions with poly(ADP-ribose). The profiles of poly(ADP-ribose) binding nuclear matrix proteins appeared to be tissue-specific and changed during postnatal development in the testis. The isolation and analysis of endogenous poly-(ADP-ribose) from rat testes showed that the ADP-ribose polymers that bind nuclear matrix proteins in vitro are also present under physiologic conditions in vivo. These results further substantiate the possibility that poly(ADP-ribose) may affect chromatin functions through noncovalent interaction with specific protein targets, including nuclear matrix components.

Animals↗
PubMed1992

Catecholamines stimulate testicular testosterone release of the immature golden hamster via interaction with alpha- and beta-adrenergic receptors.

Several lines of evidence suggest that catecholamines are involved in the regulation of the development of the testis. We have therefore investigated the ability of testicular parenchyma (decapsulated pieces of testes) from 18 to 20-day-old golden hamsters to respond to catecholaminergic stimuli in vitro. Norepinephrine and epinephrine, as well as the beta-receptor agonist isoproterenol and the alpha-adrenoreceptor agonist phenylephrine were able to significantly stimulate testicular testosterone production. Dopamine and serotonin were not effective. The stimulatory action of norepinephrine on testosterone production was dependent on the concentration. In incubations of testes with human chorionic gonadotropin (hCG) and norepinephrine, no synergistic effects on testosterone release were observed. The stimulatory effect of norepinephrine could be partially blocked by incubation with beta-receptor antagonist propranolol, or with alpha-receptor antagonist prazosin, while a combination of propranolol and prazosin completely inhibited the norepinephrine-induced testosterone production. Moreover, isoproterenol and phenylephrine in combination stimulated testosterone more than either drug did alone. Measurements of concentrations of norepinephrine and epinephrine in testicular homogenates revealed higher values for these catecholamines than in the plasma, implying that catecholamine levels in the interstitial spaces of the testis might be in the range of concentrations effectively stimulating testosterone production in vitro. This suggests that in the immature testis of the golden hamster, catecholamines acting through both alpha- and beta-adrenergic receptors may be potent physiological stimulators of testosterone production.

Animals↗
PubMed2005

Effects of photoperiod and food availability on growth, leptin, sexual maturation and maintenance in the Mongolian gerbils (Meriones unguiculatus).

Reproductive activity of Mongolian gerbils is regulated by photoperiod nevertheless body weight regulation is controlled without ambient photoperiod. Food intake is a major factor affecting rodent reproductive efficiency. Leptin is a hormone secreted by adipose tissue and modulates food intake, energy expenditure and body fat stores. In this study we studied the interaction of photoperiod and food availability on growth, sexual maturation and leptin concentration in the male and female gerbils. Gerbils were gestated and reared in either 14L:10D or 2L:22D. At weaning, gerbils were housed individually and divided into three groups: fed ad libitum, fed 80% of ad libitum or fed 60% of ad libitum. Body weights were recorded at weaning and every week thereafter. After twelve weeks of treatment, animals were sacrificed and testes and uterine weights were determined and blood was collected for leptin measurement. Food restriction reduced body weight and inhibited reproductive development. Absolute paired testis weights were similar in ad lib and 80% of ad lib groups but significantly different compared with the 60% of ad lib group in both photoperiods. Body weights were also directly dependent upon the level of food restriction. Uterine mass was only affected in the 60% of ad lib group in 14L but both food restriction levels significantly affected the uterine weights in 2L. Significant variations were found in leptin profiles. Leptin concentration was highest in ad lib and 80% of ad lib groups and lowest in 60% of ad lib groups. These results suggest that the reproductive activity of Mongolian gerbils is sensitive to food intake and multiple potential environmental cues (e.g., food availability, temperature) can be utilized.

Animals↗
PubMed1979

Side-by-side pairing of the XY bivalent in spermatocytes and the ubiquity of the H-Y locus.

The pairing mechanism of the XY bivalent, the possibility of crossing-over between X and Y chromosomes during meiotic prophase, and the location of the H-Y locus are of interest with regard to genetic control mechanisms, male gametogenesis, and testicular organization. A whole-mount electron microscope technique has permitted the study of a large number of mouse and hamster spermatocytes to evaluate the spatial relationship of sex chromosomes and autosomes. X and Y chromosomes showed a transient, extensive side-by-side pairing segment along most of the length of the Y chromosome. This extensive pairing segment may cause genetic exchange between X and Y chromosomes. The finding of a small unpaired paracentromeric region of the Y chromosome could be related to a locus of totally sex-linked gene(s) that determine the development of the testis from the undifferentiated embryonic gonad.

Animals↗
PubMed1976

Studies on the accessory reproductive organs in the drake. 2. Macroscopic and microscopic observatorys on the cloaca of the drake with special reference to the ejaculatory groove region.

The anatomical structure of the ejaculatory groove region (EGR) of the drake was investigated macro- and microscopically in connection with its function. The EGR covers a part of the urodeum and the second fold of the cloaca. The EGR is unique to the males and is characterized by red colored appearance and less smooth surface of the mucosa. The mucosa of EGR forms folds giving less smooth surface to it and is lined with psuedostratified columnar epithelium. A vascular layer which contains many capillaries and lymphocytes and gives red color to the mucosa lies just beneath the epithelium. The EGR develops at puberty together with the developments of the testis and the penis. Blood supply and the arrangement of the lymphatic sinuses of EGR were described and their functions were discussed.

Animals↗
PubMed2002

Organ-specific cytokine polarization induced by adoptive transfer of transgenic T cells.

There are two distinct phenotypes of T cell cytokine responses that lead to different effector functions and different outcomes in disease processes. Although evidence suggests a possible role of the local microenvironment in the differentiation or localization of T cells with these phenotypes, there are no examples of divergent T cell cytokine phenotypes with the same Ag specificity concurrently existing in different tissue compartments. Using a CD8(+) T cell adoptive transfer model for graft-vs-host disease, we demonstrate that a potent type 2 cytokine response develops in the spleen while a potent type 1 cytokine response simultaneously develops in the testis. These experiments demonstrate for the first time that cytokine production can be oppositely polarized in different organs of the same individual. This may have important implications for organ-specific pathology in infection or autoimmunity: infections or autoimmune diseases that affect multiple organs may have heterogeneity in tissue cytokine responses that is not revealed in systemic lymphocyte cytokine responses. Therefore, attempts to modulate the immune response phenotype may ameliorate pathology in one organ while exacerbating pathology in another.

Adoptive Transfer↗
PubMed2000

Carbohydrates mediate sperm-ovum adhesion and triggering of the acrosome reaction.

The fertilization process is the net result of a complex sequence of events that collectively result in the fusion of the opposite gametes. The male gamete undergoes continuous morphological and biochemical modifications during sperm development in the testis (spermatogenesis), maturation in the epididymis, and capacitation in the female reproductive tract. Only the capacitated spermatozoa are able to recognize and bind to the bioactive glycan residue(s) on the ovum's extracellular coat, the zona pellucida (ZP). Sperm-zona binding in the mouse and several other species is believed to take place in two stages. First, capacitated (acrosome-intact) spermatozoa loosely and reversibly adhere to the zona-intact ovum. In the second stage tight irreversible binding occurs. Both types of bindings are attributed to the presence of glycan-binding proteins (receptors) on the sperm plasma membrane and their complementary bioactive glycan units (ligands) on the surface of the ZP. The carbohydrate-mediated adhesion event initiates a signal transduction cascade resulting in the exocytosis of acrosomal contents. This step is believed to be prerequisite which allows the hyperactivated acrosome-reacted spermatozoa to penetrate the ZP and fertilize the ovum. This review focuses on the role of carbohydrate residues in sperm-ovum interaction, and triggering of the acrosome reaction. I have attempted to discuss extensive progress that has been made to enhance our understanding of the well programmed multiple molecular events necessary for successful fertilization. This review will identify these events, and discuss the functional significance of carbohydrates in these events.

Acrosome Reaction↗
PubMed2004

[GnRH deficiency: new insights from genetics].

The acquisition of a sexually dimorphic phenotype is a critical event in mammalian development. Hypogonadotropic hypogonadism (HH) results from impaired secretion of GnRH. The patients display with delayed puberty, micropenis and cryptorchidism in the male reflecting gonadotropin insufficiency, and amenorrhea in the female. Kallmann's syndrome (KS) is defined by the association of HH and anosmia or hyposmia (absent smelling sense). Segregation analysis in familial cases has demonstrated diverse inheritance patterns, suggesting the existence of several genes regulating GnRH secretion. The X-linked form of the disease was associated with a genetic defect in the KALI gene located on the Xp22.3 region. KAL1 gene encodes an extracellular matrix glycoprotein anosmin-1, which facilitates neuronal growth and migration. Abnormalities in the migratory processes of the GnRH neurons with the olfactory neurons explain the association of HH with anosmia. Recently, mutations in the FGF recepteur 1 (FGFR1) gene were found in KS with autosomal dominant mode of inheritance. The role of FGFR1 in the function of reproduction requires further investigation. Besides HH with anosmia, there are isolated HH (IHH). No human GnRH mutations have been reported although hypogonadal mice due to a GnRH gene deletion exist. In patients with idiopathic HH and without anosmia an increasing number of GnRH receptor (GnRHR) mutations have been described which represent about 50% of familial cases. The clinical features are highly variable and there is a good relationship between genotype and phenotype. A complete loss of function is associated with the most severe phenotype with resistance to pulsatile GnRH treatment, absence of puberty and cryptorchidism in the male. In contrast, milder loss of function mutations causes incomplete failure of pubertal development. The preponderant role of GnRH in the secretion of LH by the gonadotrophs explains the difference of the phenotype between male and female with partial GnRH resistance. Affected females can have spontaneous telarche and normal breast development while affected males exhibit no pubertal development but normal testis volume, a feature described as "fertile-eunuch". High-dose pulsatile GnRH has been used to induce ovulation. Another gene, called GPR54, responsible for idiopathic HH has been recently described by segregation analysis in two different consanguineous families. The GPR54 gene is an orphan receptor, and its putative ligand is the product of the KISS-1 gene, called metastine. Their roles in the function of reproduction are still unknown.

Amino Acid Sequence↗
PubMed1977

[Mesothelioma of the tunica vaginalis].

After a brief review of the pertaining literature, the case of a 63 year old male patient with a histologically confirmed mesothelioma starting from the tunica vaginalis of the testis is described. The rare tumour developed after an injury of the testis suffered 15 years earlier.

Humans↗
PubMed1994

[Study of sex determination gene (SRY) in 46,XY gonadal dysgenesis].

During mammalian embryogenesis, the presence of the SRY gene determines the bipotential gonad to develop as a testis. 46,XY sex reversal has been described in man. It is associated with an essentially female phenotype and a streak gonad. In a collaborative study, we analysed 36 patients with a 46,XY sex reversal. The testis determining region of the Y chromosome was analysed by Southern blotting and by DGGE analysis of the SRY open reading frame (orf). We found a total of 7 mutations in the testis determining region including the SRY gene. This brings to 19 the total number of mutations in SRY associated with sex reversal. No relationship was found between the SRY status and the presence or absence of gonadoblastoma. However, a correlation was observed between the SRY genotype and the histology of the gonad. A mutant in SRY is associated with a completely dysgenetic gonad. The presence of immature testicular tubules is usually observed when SRY is normal. These latter results suggest the existence of as yet unidentified testis determining genes.

DNA-Binding Proteins↗
PubMed1996

Regulation of protamine gene expression in an in vitro homologous system.

An in vitro transcription system from the trout testis nuclei was developed to study trout protamine gene expression. The protamine promoter contains, among others, two regulatory elements: 1) a cAMP-responsive element or CRE element (TGACGTCA) which is present in position 5' to TATA box, and 2) GC box (CCGCCC) which is present in position 3' to TATA box. The removal of the CRE-binding protein by titration (by the addition of appropriate oligonucleotides to the incubation mixture) resulted in a decrease in transcription of the protamine gene. These results were confirmed by experiments in which the pure CRE-binding factor (TPBP1) was used, as well as by those where a stimulatory effect of cAMP on protamine promoter transcription was observed. On the other hand, addition of oligonucleotides containing the GC-box sequence enhanced the protamine gene transcription indicating that the protein (Sp1 like) which binds to this sequence acts as a repressor of protamine gene expression. These results confirm the previously proposed model which suggested that the GC box played a role in negative regulation of the protamine gene expression. Involvement of some other factors in this process was also discussed.

Animals↗
PubMed1998

Overexpression of BSAP/Pax-5 inhibits switching to IgA and enhances switching to IgE in the I.29 mu B cell line.

B cell-specific activator protein (BSAP)/Pax-5 is a paired domain DNA-binding protein expressed in the developing nervous system, testis, and in all B lineage cells, except terminally differentiated plasma cells. BSAP regulates transcription of several genes expressed in B cells and also the activity of the 3' IgH enhancer. As it has binding sites within or 5' to the switch regions of nearly all Ig heavy chain C region genes and also is known to increase transcription of the germline epsilon RNA, BSAP has been hypothesized to be involved in regulation of Ab class switch recombination. To directly examine the effects of BSAP on isotype switching, we use a tetracycline-regulated expression system to overexpress BSAP in the surface IgM+ I.29 mu B cell line, a mouse cell line that can be induced to undergo class switch recombination. We find that overexpression of BSAP inhibits switching to IgA in I.29 mu cells stimulated with LPS + TGF-beta 1 + nicotinamide, but enhances switching to IgE in cells stimulated with LPS + IL-4 + nicotinamide. Parallel to its effects on switching, overexpression of BSAP inhibits germline alpha RNA expression and the transcriptional activity of the germline alpha promoter, while enhancing activity of the germline epsilon promoter. Proliferation of I.29 mu cells is not affected in this system. The possible mechanisms and significance of the effect of BSAP on isotype switching are discussed.

Adjuvants, Immunologic↗
PubMed2003

Sex-specific apoptosis regulates sexual dimorphism in the Drosophila embryonic gonad.

Sexually dimorphic development of the gonad is essential for germ cell development and sexual reproduction. We have found that the Drosophila embryonic gonad is already sexually dimorphic at the time of initial gonad formation. Male-specific somatic gonadal precursors (msSGPs) contribute only to the testis and express a Drosophila homolog of Sox9 (Sox100B), a gene essential for testis formation in humans. The msSGPs are specified in both males and females, but are only recruited into the developing testis. In females, these cells are eliminated via programmed cell death dependent on the sex determination regulatory gene doublesex. Our work furthers the hypotheses that a conserved pathway controls gonad sexual dimorphism in diverse species and that sex-specific cell recruitment and programmed cell death are common mechanisms for creating sexual dimorphism.

Animals↗
PubMed1989

[Spermatic cord hematoma simulating torsion of testis in Henoch-Schönlein syndrome].

Henoch-Schönlein syndrome (HSS) is a systemic disease of young children characterized by colicky pain, with melena, vomiting and damage to the joints, kidneys and other organs. Surgical problems involving the gastrointestinal tract include bleeding, intussusception and perforation. Uncommon complications, caused by bleeding into brain tissue and into the scalp, muscles, chest and scrotum, are real challenges for the physician. Spermatic cord hematoma is a rare complication of HSS. Other complications of HSS mentioned in the literature which affect the male genital system include edema of the spermatic cord or testis, epididymitis, orchitis, bleeding, Morgagni cyst, or hematoma surrounding the testis. Considering the low incidence of testicular torsion in HSS, we believe that when a patient with HSS develops acute testicular pain, noninvasive diagnostic procedures such as Doppler, ultrasound and radioisotope scans should be performed in the hope of avoiding unnecessary surgical interventions. A 2-year-old boy with HSS in whom torsion of the testis developed is reported.

Child, Preschool↗
PubMed1993

Testicular weight, Sertoli cell number, daily sperm production, and sperm output of sexually mature rabbits after neonatal or prepubertal hemicastration.

The present study was conducted to investigate the influence of hemicastration and age at hemicastration on the subsequent testicular development of male rabbits through sexual maturity. Thirty New Zealand white rabbits were left intact or were hemicastrated on Day 35, 49, 77, or 105 postconception. Beginning at 7 mo of age, ejaculates were collected every other day for 1 mo, and the last ten ejaculates were used to quantify daily sperm output. At 8 mo, the rabbits were killed and their carcases, testes, testicular capsules, and epididymides were weighed. Testicular tissue was processed for quantification of sperm production rates by enumeration of homogenization-resistant spermatids and via histometric evaluation. Regardless of the age at hemicastration, this manipulation did not alter the development of the remaining testis as assessed from testis weight, numbers of Sertoli cells per testis, daily sperm production, or sperm output (p > 0.05). On the basis of these findings, it would appear that the development of the spermatogenic capacity of the remaining testis of the rabbit is not altered appreciably by hemicastration at a young age.

Animals↗
PubMed1988

Embryology of the gonad with reference to special tumors of the ovary and testis.

The ovaries and testes have very similar development patterns until about the fourth month of embryonic life. A review of the similar development (until the fourth month) provides an explanation for the origin of tumors commonly associated with ovarian tissue appearing in the testis and vice versa. Embryonic surface epithelium gives rise to mesothelial tissue from which the common epithelial tumors arise in the ovary. Since these cells disappear from the testis when the tunica albuginea develops, this offers an explanation for the lack of common epithelial tumors in the testis. The embryonic gonadal tissue or sex cord epithelium and the primitive germ cells give rise to similar tumors in both the ovary and the testis. The extraembryonal tumors arise from the extraembryonal cells and trophoblastic cells, which give rise to the endodermal sinus tumors and choriocarcinomas, respectively. Since there is such a similarity in the development of the ovary and testis with the potential for residual cells to remain, an explanation is offered for the development of similar tumors in the ovary and the testis.

Female↗