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PubMed1975

Properties of chromatin subunits from developing trout testis.

When a sample of trout testis nuclei is digested with micrococcal nuclease, the DNA is cleaved almost entirely to discrete fragments approximately 200 base pairs long and multiples thereof. The same DNA fragments can be obtained when isolated chromatin, as opposed to intact nuclei, is nuclease digested. These DNA fragments can also be found in discrete chromatin "subunits" isolated from nuclease-digested nuclei. Sedimentation through sucrose gradients or velocity sedimentation in an analytical ultracentrifuge separates these chromatin subunits into 11 S (monomer), 16 S (dimer), and 22 S (trimer) etc. species. Subunits can also be fractionated on a Sepharose 2B column equilibrated and run in low salt. High salt (greater than 40 mM NaCl) or divalent cations (congruent to 5 mM) cause subunit precipitation. Chromatin subunits have a protein to DNA ratio of approximately 1.2 and contain all the histones, including the trout-specific histone T. There are, however, no detectable nonhistone chromosomal proteins. Mg-2+ precipitates of the 11 S chromatin monomers, when pelleted, are thin and clear, while oligomer Mg-2+ pellets are thick and white. This could reflect a more symmetrical or ordered packing of 11 S monomers, which are deficient in histone I. This histone may cross-link the larger oligomers, resulting in a disordered Mg-2+ complex. These results are consistent with the subunit model of chromatin structure, based on 200 base pair long regions of DNA associated with histones. These subunits would be separated by nuclease-sensitive DNA spacer regions and cross-linked by histone I.

Animals↗
PubMed1975

Sites of in vivo histone methylation in developing trout testis.

Specific lysyl residues of trout testis histones H3 and H4 are methylated partially during rainbow trout spermatogenesis. Histones H1, H2A, H2B, and protamine are not methylated. The single site (lysine 20) in histone H4 and the two major sites (lysines 9 and 27) in histone H3 are homologous to those determined for other organisms, but an additional minor site (lysine 4) occurs in histone H3. As described for calf thymus, both histones H3 and H4 contain epsilon-N-mono- and dimethyllysine, while histone H3 contains in addition, epsilon-N-trimethyllysine. The trout-specific histone H6, which accounts for 0.5 to 1.0% of total histone, contains a sequence for residues 3 to 5,-Arg-Lys-Ser-, which is the same as one methylated in histones H3, at lysines 9 and 27. However, histone H6 yields only trace amounts of [3H]methyl incorporation and no detectable methyllysines on amino acid analysis.

Alanine↗
PubMed1980

Effect of combined gonadotropin-thyrotropin treatment on development of testis and ovarium in the chickling.

Both TSH and gonadotropins stimulate the gonads in the perinatal period. Gonadotropins influence primarily the parenchyma and they induce an increase in the diameter of seminiferous tubules, and of the thickness of the ovarian cortex. TSH acts primarily on the interstice, but it acts also on the parenchyma and this action is more pronounced in the testis than in the ovary. The hormones can replace each other, and gonadotropins enhance the effect of TSH on the interstice.

Animals↗
PubMed1988

Ultrastructural abnormalities of epididymal tissues in XXSxr pseudomale (sex-reversed) mice.

Sex reversed (Sxr), a duplication of the Y chromosomal testis-determining factor in mice, causes testis development in XXSxr animals. No effects of Sxr on nongonadal organs are expected. However, we have previously shown that the epididymis of XXSxr pseudomale (sex-reversed) mice lacks the Initial Segment. In the present study we examined the ultrastructure of the head of the epididymis of adult and 21-day old XXSxr pseudomale mice. Epithelial cells of both adult and juvenile XXSxr animals contain numerous vesicles, some within mitochondria. The basal lamina is thickened and infolded. The periepithelial layer is abnormally thick, with distorted smooth muscle cells and fibrocytes that also contain lysosomelike vesicles, often in mitochondria, and excessively wide intercellular spaces. Normal collagen fibrils are infrequent; they are in part replaced by wisps of nondiscrete material, possibly immature collagen. Sxr is known to affect spermatogenesis and Sertoli cells. The abnormal conjugation of sex-determining genes in XXSxr appears also to subvert mesenchymal-epithelial development in both epididymis and testis. We believe the most likely explanation of our data is that the XXSxr genotype is not testis specific but also influences the epididymis directly.

Animals↗
PubMedDate not supplied

[Andrological findings in hemicastration, lack of a testis, and reduced testicular volume].

In a catamnestic study an analysis of the clinical results as well as of the spermatograms are reported on 545 andrological patients with "atrophy" (that means reduced testis volume) or absence of one testis and a contralaterally normal developed testis. It can be demonstrated that there do not exist any differences concerning the size and consistency of the present testis and with regard to absence or lost of one testis (hemicastration). In case of testicular atrophy exists a more disadvantageous reproductive function. In case of tumor as a reason for hemicastration the teratoma shows better conditions for the quality of the spermatograms and for reproduction. Accordingly the histological findings of the testis after hemicastration/absence are not so large in the present remained testis. In cases of one-sided orchitis the spermatogram quality is better than in one-sided varicocele with atrophy at the same side.

Adolescent↗
PubMed1991

[Nuclear triiodothyronine receptors in the testis of the growing rat are regulated by the thyroid status].

The effects of thyroid status on the binding capacity, association constant (Ka) and receptor occupancy during postnatal rat testis development were evaluated. Hypothyroidism (induced by oral administration of 0.05% methimazole from the day of birth) increased the total T3 binding capacity in the testis, retarding the normal developmental decrease in T3 receptor number (mean maximal binding capacities estimated by Scatchard analysis for 21-day-old eu- and hypothyroid rats were 117 and 173 fmol/mg DNA, respectively). The rat thyroid status also affected the percentage of T3 receptor occupancy but not the affinity of binding (as measured by Ka). The postnatal developmental changes in T3 binding capacity induced by hypothyroidism were completely reversed by T3 replacement. These results suggest that T3 nuclear receptors in the developing rat testis are modulated by thyroid hormones.

Animals↗
PubMed1991

Sex determination in mammals. How many genes are involved?

The genetic mechanisms of sex determination in mammals have not yet been clarified. Y-linked and X-linked zinc finger genes from humans and mice were recently cloned and characterized. The Y-linked zinc finger gene was originally thought to be the testis-determining factor. However, at the present time, it seems clear that this gene is not the master gene triggering the cascade of events leading to sex determination. The human testis-determining factor gene is known to be located in the nonhomologous region of the short arm of the Y chromosome, close to an Alu repeat that marks the boundary of the pseudoautosomal region. Lately, this region has been found to contain a new gene that is a strong candidate for the male-determining factor. Data on humans and on laboratory and vole mice showing abnormalities of the sex determination mechanisms indicate that testis development depends on the presence of a testis-determining factor gene functioning in cooperation with X-linked and autosomal genes. Ovary development would depend on the absence of the testis-determining factor and perhaps on an alternative splicing of the transcripts from autosomal and X-linked genes involved in sex determination.

Animals↗
PubMed1990

[The influence of chemotherapy on testicular function of boys with acute lymphoblastic leukemia].

In order to investigate gonadal development of boys after chemotherapy, testicular biopsy specimens, which were obtained from 16 boys within 6 months after completion of the therapy for acute lymphoblastic leukemia, were assessed and their gonadal function was examined. More than half of them showed a decrease of Mean Tubular Diameter and Johnsen's Score Count, but no specimen showed a decrease of Tubular Fertility Index. Seventeen healed patients consisting of 12 biopsied and 5 non-biopsied cases were examined as to the volume of testis, development of the genital organ, skeletal age, plasma LH, FSH, testosterone, LH-RH test and HCG test. The period of follow-up after completion of chemotherapy varied from 1 month to 5 years. All patients showed testis volume, development of external genitalia and skeletal age suitable for their age. Some patients who were examined within 2 years after completion of chemotherapy, showed abnormal endocrine functions, but other patients examined after more than two years showed normal endocrine functions except a case who received testicular irradiation. Semen analysis in one case revealed density and motility within normal range. These data indicate that chemotherapy of acute lymphoblastic leukemia in boys damages testicular function, but more than 2 years later the spermatogenesis as well as endocrine function is expected to recover gradually.

Adolescent↗
PubMed1990

The testis and tissue transplantation: historical aspects.

Transplantation experiments involving the testis have been performed since the days of John Hunter, who transplanted a testis into the belly of a hen. The first person to use the testis as a site of transplantation appears to have been Sand, who found in 1919 that an ovary transplanted into the substance of the testis developed follicles. By 1970, there was considerable evidence that the testis under some circumstances was a relatively favorable site for graft survival. However, much of the evidence was equivocal, and the immunological privilege was by no means complete.

Animals↗
PubMed1981

Regulation of the synthesis of lactate dehydrogenase-X during spermatogenesis in the mouse.

Total mouse testis RNA directs the synthesis of the sperm-specific C subunit of lactate dehydrogenase-X (LDH-X) when translated in a cell-free system derived from rabbit reticulocytes. The newly synthesized C subunits were isolated by immunoprecipitation with antibody specific for this isozyme, and quantitated by electrophoresis on SDS polyacrylamide gels. The amount of radioactivity incorporated into the enzyme subunit was directly proportional to the amount of testis RNA added to the translational system, thereby providing a sensitive and reliable method for assessing relative LDH-X mRNA activity. A combination of sucrose gradient centrifugation and oligo(dT)-cellulose chromatography resulted in a 23-fold purification of LDH-X mRNA over total cytoplasmic testis RNA. Analysis of LDH-X mRNA activity in the developing testis indicated that the appearance of functional LDH-X mRNA activity coincides with the appearance of LDH-X catalytic activity at 14 d postpartum. Measurement of LDH-X mRNA levels in separated testis cell populations prepared by centrifugal elutriation demonstrated that LDH-X mRNA represents 0.17-0.18% of the total functional mRNA activity in fractions enriched in pachytene spermatocytes and round spermatids, but only 0.09-0.10% of the translation products of elongated spermatids.

Animals↗
PubMed1991

Quantitative analysis of the development of genital organs from the urogenital sinus of the fetal male mouse treated prenatally with a 5 alpha-reductase inhibitor.

The role of 5 alpha-dihydrotestosterone (DHT) in the development of the genital organs and in the differentiation of the genital tract into prostate, coagulating gland (CG), bulbo-urethral gland (BUG) and seminal vesicle (SV) in male mice exposed prenatally to the 5 alpha-reductase inhibitor 6-methylene-4-pregnene-3,20-dione (6-MP) has been examined quantitatively. Female ICR mice were given 7 daily s.c. injections of the inhibitor (400 mg/day) starting on day 12 of gestation and the experiment was terminated on day 19 when the fetuses were removed by Caesarean section. In the prenatally 6-MP-exposed male mice the anogenital distance was significantly shorter than in the controls. Feminization of the nipples and hypospadias of the phallic urethra were noted. Development of prostate, CG and BUG was significantly suppressed. SV and testis development were not affected. These results lend further support to the conclusion that DHT is necessary for the development of the urogenital sinus (prostate, CG and BUG) and penis, and for the regression of the nipples in male mice. Reproductive abnormalities were not found in 90-day-old mice of both sexes exposed to 6-MP in utero. The 6-MP-exposed male and female mice had a normal reproductive capacity when mated with normal mice. These results show that 6-MP-induced growth retardation of reproductive organs is evident on day 19 of gestation, but that such retardation is no longer apparent in the adult.

5-alpha Reductase Inhibitors↗
PubMed1992

Sex-determining region Y (SRY) in a patient with 46,XX true hermaphroditism.

Using a polymerase chain reaction method, a search for Y-specific DNA sequences was made in samples derived from tissues of a 46,XX true hermaphrodite. We found a sequence of SRY in the ovotestis, skin and leukocytes. Other DNA sequences, which covered the pseudoautosomal boundary region, amelogenin gene and DYZ1 locus of Y-chromosome were not detected. The SRY gene detected in the patient by the polymerase chain reaction was not detected by Southern blot analysis, using the SRY fragment as a probe. These findings suggest that in the patient there is a mosaicism of cells with and without part of the Y chromosome, including the SRY sequence. As the SRY sequence was responsible for the development of the gonadal primordium to the ovotestis, SRY seems essential for gonadal differentiation in testis development.

Base Sequence↗
PubMed1991

Cell-cell interactions and the regulation of testis function.

Regulatory interactions have been shown to occur between all the testicular cell types considered. The paracrine factors mediating these interactions generally influence either cellular growth or differentiation. The regulation of cellular growth is essential in the developing testis and is required for the maintenance of spermatogenesis in the adult testis. The rapid rate of germinal cell proliferation and the continuous but slowed growth of the peritubular cells and Leydig cells requires the presence of specific growth factors in the adult. Therefore, cell-cell interactions have evolved that involve growth factors such as IGF, TGF-alpha, TGF-beta and NGF. Other growth factors such as FGF or less characterized components like the seminiferous growth factor (SGF) also may be involved in the paracrine regulation of testis cell growth. An alternate cellular parameter to cell growth to consider is the regulation of cellular function and differentiation. A number of endocrine agents and locally produced paracrine factors have been shown to control and maintain testis cell function and differentiation. Cell-cell interactions mediated by factors such as androgens, POMC peptides, and PModS are all primarily directed at the regulation of cellular differentiation. Therefore, the agents which mediate cell-cell interactions in the testis can generally be categorized into factors that regulate cell growth or those which influence cellular differentiation. The specific cell-cell interactions identified will likely be the first of a large number of cellular interactions yet to be investigated. Although a number of potentially important cell-cell interactions have been identified, future research will require the elucidation of the in vivo physiological significance of these interactions. The existence of different cell types and potential cell-cell interactions in a tissue implies that the actions of an endocrine agent on a tissue will not simply involve a single hormone and single cell. The endocrine regulation of testis function will have effects on cell-cell interactions and be affected by local cell-cell interactions. The ability of LH to influence Leydig cell androgen production promotes a cascade of interactions mediated through several cell types to maintain the process of spermatogenesis. FSH actions on Sertoli cells also promote cell-cell interactions that influence germinal cell development, peritubular myoid cell differentiation and Leydig cell function. Therefore, elucidation of the endocrine regulation of testis function requires an understanding of the local cell-cell interactions in the testis.

Animals↗
PubMed1988

H-Y antigen and sex determination.

The primary development of a male rather than a female gonad in mammals is determined by the presence of a Y chromosome. The other property unique to the Y chromosome is the occurrence of a cell-surface antigen (designated H-Y) which distinguishes male from female. Thus it was determined that male grafts were rejected by otherwise histocompatible females of the same inbred strain and later that H-Y-specific cytolytic T cells were produced by these grafted mice. When it was determined that females grafted with male skin produced antibody defining a serologically detectable male antigen (which may or may not be the same as H-Y), further immunogenetic analysis of this antigenic system became possible in terms of humoral and cellular factors. By using this assay it was demonstrated that the antigen was phylogenetically conserved and that it was expressed in the male mouse embryo as early as the 8-cell stage of development. The notion that H-Y was a single molecular species responsible for triggering the indifferent gonad to differentiate into the testis became a widely accepted hypothesis. In this report the H-Y antigenic system is traced historically from its original description to the role played in testis development. Data are presented which suggest that although H-Y is a male-specific factor and may play a role in male sex determination, it is unlikely that it is the primary inducer of testis differentiation.

Animals↗
PubMed1992

Cloning and mutational analysis of SRY.

A candidate for the male sex-determining gene has recently been isolated. This sex-determining gene (SRY) has been found to be mutated in some individuals with failed testis development, and, in mouse transgenesis, the SRY murine homologue (Sry) causes female-to-male sex reversal. The cloning of SRY should facilitate the characterisation of other genes in the testis-determining pathway and provide information on the mechanism of mammalian developmental decisions.

Animals↗
PubMed1988

Müllerian inhibiting substance production and testicular migration and descent in the pouch young of a marsupial.

The ontogeny of Müllerian inhibiting substance (MIS) production by the developing testis of an Australian marsupial, the tammar wallaby (Macropus eugenii), was determined during pouch life using an organ-culture bioassay of mouse fetal urogenital ridge. This information was related to the morphological events during testicular migration and descent. MIS biological activity was found in testes (but not ovaries or liver) of pouch young from 2 to 85 days of age. MIS production had commenced by day 2, which is within a day of the first gross morphological signs of testicular differentiation. Müllerian duct regression occurred between 10 and 30 days, which partly coincided with testicular migration to the inguinal region and enlargement of the gubernacular bulb (15 to 30 days). These observations are consistent with the hypothesis that MIS may be involved in testicular transabdominal migration. The epididymis commenced development and growth only after the testis had descended through the inguinal ring. This provides no support for the suggestion that the epididymis is involved in testicular descent into the scrotum. The basic sequence of events in post-testicular sexual differentiation in the wallaby is sufficiently similar to that seen in eutherian mammals to make it an excellent experimental model for future studies of testicular differentiation, migration and descent.

Animals↗
PubMed1989

Normal testis determination in the mouse depends on genetic interaction of a locus on chromosome 17 and the Y chromosome.

We previously described a locus on chromosome (Chr) 17 of the mouse that is critical for normal testis development. This locus was designated "T-associated sex reversal" (Tas) because it segregated with the dominant brachyury allele hairpin tail (Thp) and caused gonads of C57BL/6J XY, Thp/+ individuals to develop as ovaries or ovotestes rather than as testes. To clarify the inheritance of Tas, we investigated the effects of T-Orleans (TOrl), another brachyury mutation, on gonad development. We found that gonads of C57BL/6J XY, Thp/+ and TOrl/+ mice develop ovarian tissue if the Y chromosome is derived from the AKR/J inbred strain, whereas normal testicular development occurs in the presence of a Y chromosome derived from the C57BL/6J inbred strain. From these observations we conclude that: (1) Tas is located in a region on Chr 17 common to the deletions associated with Thp, and TOrl, and (2) the Y-linked testis determining gene, Tdy, carried by the AKR/J inbred strain differs from that of the C57BL/6J inbred strain. We suggest that in mammals Tdy is not the sole testis determinant because autosomal loci must be genetically compatible with Tdy for normal testicular development.

Animals↗