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PubMed1999

Cellular immunolocalization of occludin during embryonic and postnatal development of the mouse testis and epididymis.

Cellular junctions in the testis and epididymis play crucial roles for the development and maturation of spermatozoa. In the testis, tight junctions between Sertoli cells form a functional blood testis barrier between 10 and 16 days of age, whereas the tight junctional blood epididymal barrier between adjacent epithelial cells is formed between days 18 and 21. In the present study, occludin, a constituent integral membrane protein of tight junctions, was localized by immunofluorescent confocal microscopy in embryonic (days 13.5-18.5), postnatal (days 5-23) and adult (day 70) mouse testes and epididymides to correlate its expression with the onset of tight junctions and eventual formation of these barriers. At embryonic days 13.5 and 16.5, low diffuse cytoplasmic levels of occludin were observed in cells of the testicular cords. By embryonic day 18.5, the level of occludin was still low but appeared as a filiform-like network streaming toward the center of the cord. At postnatal days 5 and 7 immunostaining became more intense and appeared to outline the periphery of Sertoli cells of seminiferous tubules. Postnatal day 14 marked the appearance of an intense, focal band-like localization of occludin at the base of the tubules, correlating with the appearance of a functional blood-testis barrier. By day 23 and in adults, expression of occludin was noted at the base of the tubule appearing as intense, wavy, discontinuous bands similar in appearance irrespective of the stage of the seminiferous epithelium cycle. In the developing epididymis, intense cytoplasmic immunostaining was present in epithelial cells of many epididymal tubules at embryonic day 13.5. By embryonic day 16.5, intense occludin immunostaining appeared along the lateral plasma membranes of epithelial cells, whereas at embryonic day 18.5, immunostaining was punctate and apically located, suggesting the presence of tight junctions by this age; similar immunostaining was noted at postnatal days 5 and 7. In the adult epididymis, distinct punctate apical staining was observed between adjacent principal cells of all epididymal regions except the proximal initial segment, where occludin was found only in association with narrow cells. These results indicate that in the epididymis, the appearance of occludin at apical sites between adjacent epithelial cells occurs during embryonic development suggesting that tight junctions form earlier than in the testis. While occludin was expressed in a similar pattern between Sertoli cells at all stages of the cycle in the adult testis, its expression in the adult epididymis was cell- and region-specific. Taken together these data suggest that different factors regulate occludin expression in the testis and epididymis.

Aging↗
PubMed2000

Comparative effects of neonatal exposure of male rats to potent and weak (environmental) estrogens on spermatogenesis at puberty and the relationship to adult testis size and fertility: evidence for stimulatory effects of low estrogen levels.

This study investigated whether neonatal exposure of male rats to estrogenic compounds altered pubertal spermatogenesis (days 18 and 25) and whether the changes observed resulted in long-term changes in testis size, mating, or fertility (days 90-100). Rats were treated neonatally with a range of doses (0.01-10 microg) of diethylstilbestrol (DES; administered on alternate days from days 2-12), a high dose of octylphenol (OP; 2 mg administered daily from days 2-12) or bisphenol A (Bis-A; 0.5 mg administered daily from days 2-12), or vehicle, while maintained on a standard soy-containing diet. The effect on the same parameters of rearing control animals on a soy-free diet was also assessed as was the effect of administering such animals genistein (4 mg/kg/day daily from days 2-18). Testis weight, seminiferous tubule lumen formation, the germ cell apoptotic index (apoptotic/viable germ cell nuclear volume), and spermatocyte nuclear volume per unit Sertoli cell nuclear volume were used to characterize pubertal spermatogenesis. Compared with (soy-fed) controls, DES administration caused dose-dependent retardation of pubertal spermatogenesis on day 18, as evidenced by decreases in testis weight, lumen formation, and spermatocyte nuclear volume per unit Sertoli cell and elevation of the germ cell apoptotic index. However, the two lowest doses of DES (0.1 and 0.01 microg) significantly increased spermatocyte nuclear volume per unit Sertoli cell. Similarly, treatment with either OP or Bis-A significantly advanced this and some of the other aspects of pubertal spermatogenesis. Maintenance of control animals on a soy-free diet also significantly advanced lumen formation and spermatocyte nuclear volume per unit Sertoli cell compared with controls fed a soy-containing diet. Administration of genistein reversed the stimulatory effects of a soy-free diet and significantly retarded most measures of pubertal spermatogenesis. In general, plasma FSH levels in the treatment groups changed in parallel to the spermatogenic changes (reduced when pubertal spermatogenesis retarded, increased when pubertal spermatogenesis advanced). By day 25, although the changes in FSH levels largely persisted, all of the stimulatory effects on spermatogenesis seen on day 18 in the various treatment groups were no longer evident. In adulthood, testis weight was decreased dose dependently in rats treated neonatally with DES, but only the lowest dose group (0.01 microg) showed evidence of mating (3 of 6) and normal fertility (3 litters). Animals treated neonatally with OP or Bis-A had normal or increased (Bis-A) testis weights and exhibited reasonably normal mating/fertility. Animals fed a soy-free diet had significantly larger testes than controls fed a soy-containing diet, and this difference was confirmed in a much larger study of more than 24 litters, which also showed a significant decrease in plasma FSH levels and a significant increase in body weight in the males kept on a soy-free diet. Neonatal treatment with genistein did not alter adult testis weight, and although most males exhibited normal mating and fertility, a minority did not mate or were infertile. It is concluded that 1) neonatal exposure of rats to low levels of estrogens can advance the first wave of spermatogenesis at puberty, although it is unclear whether this is due to direct effects of the estrogen or to associated elevation of FSH levels; 2) the effect of high doses of OP and Bis-A on these processes is essentially benign; and 3) the presence or absence of soy or genistein in the diet has significant short-term (pubertal spermatogenesis) and long-term (body weight, testis size, FSH levels, and possibly mating) effects on males.

Aging↗
PubMed2001

Tescalcin, a novel gene encoding a putative EF-hand Ca(2+)-binding protein, Col9a3, and renin are expressed in the mouse testis during the early stages of gonadal differentiation.

To identify genes that are differentially expressed in the developing testis we used representational difference analysis of complementary DNA from gonads of mouse embryos at 13.5 days postcoitum (dpc). Three genes were identified. One of them was a novel gene termed tescalcin that encoded a putative EF-hand Ca(2+)-binding protein. The open reading frame consisted of 642 nucleotides encoding a protein with 214 amino acids. Analysis of the predicted amino acid sequence revealed an N:-myristoylation motif and several phosphorylation sites in addition to an EF-hand Ca(2+)-binding domain. TESCALCIN: messenger RNA (mRNA) was present in fetal testis, but not in ovary or mesonephros, and was restricted to the testicular cords. Its expression was first detected in the male gonad at 11.5 dpc and demonstrated a pattern consistent with a role in the testis at the early stages of testis differentiation. Tescalcin is expressed in the testis of Kit(W/W-v) mice, indicating that it is not dependent on the presence of germ cells. The other two genes identified were collagen IX alpha3 (Col9a3) and RENIN: Col9a3 expression was present at low levels in male and female gonads at 11.5 dpc. Thereafter, it was markedly up-regulated in the male, but remained very low in the female. Expression of Col9a3 was restricted to testicular cords and was also detected in testis of Kit(W/W-v) mice. RENIN: mRNA was first detected in testis at 12.5 dpc, increased thereafter, and reached a peak at 16.5 dpc. RENIN: mRNA was localized in cells of the interstitium and cells at the border between the gonad and mesonephros. Expression of RENIN: in the ovary was not detected using standard conditions.

Amino Acid Sequence↗
PubMed2004

Expression of ghrelin and its functional receptor, the type 1a growth hormone secretagogue receptor, in normal human testis and testicular tumors.

Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHS-R), has been primarily linked to the central neuroendocrine regulation of GH secretion and food intake, although additional peripheral actions of ghrelin have also been reported. In this context, the expression of ghrelin and its cognate receptor has been recently demonstrated in rat testis, suggesting a role for this molecule in the direct control of male gonadal function. However, whether this signaling system is present in human testis remains largely unexplored. In this study we report the expression and cellular location of ghrelin and its functional receptor, the type 1a GHS-R, in adult human testis. In addition, evaluation of ghrelin and GHS-R1a immunoreactivity in testicular tumors and dysgenetic tissue is presented. The expression of the mRNAs encoding ghrelin and GHS-R1a was demonstrated in human testis specimens by RT-PCR, followed by direct sequencing. In normal testis, ghrelin immunostaining was demonstrated in interstitial Leydig cells and, at lower intensity, in Sertoli cells within the seminiferous tubules. In contrast, ghrelin was not detected in germ cells at any stage of spermatogenesis. The cognate ghrelin receptor showed a wider pattern of cellular distribution, with detectable GHS-R1a protein in germ cells, mainly in pachytene spermatocytes, as well as in somatic Sertoli and Leydig cells. Ghrelin immunoreactivity was absent in poorly differentiated Leydig cell tumor, which retained the expression of GHS-R1a peptide. In contrast, highly differentiated Leydig cell tumors expressed both the ligand and the receptor. The expression of ghrelin and GHS-R1a was also detected in dysgenetic Sertoli cell-only seminiferous tubules, whereas germ cell tumors (seminoma and embryonal carcinoma) were negative for ghrelin and were weakly positive for GHS-R1a. In conclusion, our results demonstrate that ghrelin and the type 1a GHS-R are expressed in adult human testis and testicular tumors. Overall, the expression of ghrelin and its functional receptor in human and rat testis, with roughly similar patterns of cellular distribution, is highly suggestive of a conserved role for this newly discovered molecule in the regulation of mammalian testicular function.

Adult↗
PubMed1996

Estrogen metabolism and impaired spermatogenesis in germ cell tumors of the testis.

We evaluated spermatogenesis in 36 patients with germ cell tumors [11 with seminoma (S) and 25 with nonseminoma (NS)] in terms of sperm concentration and histological score (Johnsen's mean score) of spermatogenesis in the ipsilateral and contralateral testes. We also measured the steroid concentration in the spermatic vein of the tumor-bearing side and performed biochemical and immunohistochemical studies of aromatase activity of the tumor to investigate the mechanism of exocrine and endocrine testicular dysfunction, with particular emphasis on the role of estrogen metabolism. The sperm concentration was significantly lower in patients with S (42.9 +/- 40.7 x 10(8)/mL) and NS (17.6 +/- 20.8 x 10(6)/mL) compared to normal adult men (114.4 +/- 41.2 x 10(6) mL; P < 0.01). The histological score was lower in patients with NS than in patients with S. The histological score was highest in the contralateral testis, followed by the ipsilateral testis far from the tumor and the ipsilateral testis near the tumor in both the S and NS groups. Serum levels of estradiol and hCG were significantly elevated in both the systemic and spermatic veins of patients with NS compared to normal values, but they were within normal limits in patients with S. The histological score count in the contralateral testis was significantly and inversely correlated with the tumor weight and serum levels of hCG and estradiol. Aromatase activity examined in 9 tumors (5 S and 4 NS) and 6 ipsilateral nonneoplastic testis (3 S and 3 NS) was significantly higher in both neoplastic and nonneoplastic testes in NS patients (tumor, 5.343 +/- 4.027; nontumor, 14.647 +/- 7.688 pmol/h.pg protein) compared to S patients (tumor, 0.622 +/- 0.408; nontumor, 1.979 +/- 1.164 pmol/h.pg protein). Aromatase immunoreactivity was observed in Leydig cells of the nonneoplastic testis in both S and NS patients and in interstitial or stromal cells in 16 of 25 of NS patients and none of S patients. Our results suggest that impaired spermatogenesis in patients with testicular germ cell tumor is caused by increased tumor size in both NS and S patients and/or by increased aromatization and in situ estrogen production in Leydig cells of the nonneoplastic testis and in interstitial or stromal cells of the tumor in patients with NS.

Adolescent↗
PubMed1999

Cloning of two novel mammalian paralogs of relaxin/insulin family proteins and their expression in testis and kidney.

Based on sequence homology to insulin and relaxin, we have isolated two novel genes of the insulin superfamily from mouse tissues. Because these proteins show a high similarity to relaxin and relaxin-like factor (RLF or Ley I-L), they were named as RIF1 (relaxin/insulin-like factor 1) and RIF2 (relaxin/insulin-like factor 2). After RT-PCR, full-length cDNAs of RIF1 and RIF2 were obtained from mouse testis and ovary, respectively. In addition, a putative human ortholog of RIF1 was isolated from human testis. The deduced coding regions of mRIF1, mRIF2, and hRIF1 were 191, 145, and 213 amino acids, respectively, and all three proteins contain a typical signal sequence for secretion at their amino terminus. Sequence comparison indicated that RIFs encode proteins consisting of B and A subunits connected by a long C domain peptide, and the deduced mature proteins of these putative ligands are most closely related to relaxin, RLF, and insulin from different species. Northern blot analysis showed that RIF1 transcripts are approximately 1.2 kb in size and are expressed mainly in testis of mouse and human. In contrast, RIF2 message of 2.0 and 1.2 kb are preferentially expressed in mouse kidney and are lower in testis, heart, and brain. In addition, immunohistochemical analysis showed that testis expression of RIF1 is restricted to interstitial cells surrounding seminiferous tubules. In kidney, the RIF2 message is localized to selected epithelial cells of loop of Henle. The exclusive expression pattern of RIF1 and related RLF in testis interstitial cells suggested potential physiological roles of these two distinct insulin/relaxin family ligands in testis function. Additionally, the spatial expression pattern of RIF2 suggests a novel role of RIF2 in nephrophysiology. Identification of RIF polypeptides expands the family of relaxin- and insulin-like hormones and allows future elucidation of the physiological role and hormonal mechanisms for these tissue-specific factors.

Amino Acid Sequence↗
PubMed1988

The fate of fetal Leydig cells during the development of the fetal and postnatal rat testis.

The ultrastructure and developmental fate of the fetal generation of Leydig cells of the rat testis was studied from the 17th day of fetal life up to 100 days after birth. The number of fetal Leydig cells per testis was determined by light microscopic morphometric analysis of semithin plastic sections. In fetal testes (days 17-22 postconception), Leydig cells exhibited a characteristic ultrastructure, containing smooth endoplasmic reticulum, many lipid inclusions and glycogen. Testes of 17-day-old fetuses contained about 25 x 10(3) fetal Leydig cells, rapidly increasing to 90 x 10(3) per testis in 21-day-old fetuses. After birth, fetal Leydig cells per testis remained relatively constant up to 2 weeks (80-90 x 10(3) per testis) and were identified by light and electron microscopy which showed their numerous lipid inclusions, their tendency for clustering and their association with interstitial tissue fibroblasts which partly encapsulated the fetal Leydig cells. From 21-100 days after birth, fetal Leydig cell numbers were quite variable with a mean of 45-60 x 10(3) per testis. These results are the first to show that the fetal generation of Leydig cells persist in the adult testis and do not undergo early postnatal degeneration or dedifferentiation into other interstitial cells. The simultaneous occurrence of the fetal Leydig cells and the adult population of Leydig cells indicates that these cells are distinct cell generations which are developmentally unrelated.

Animals↗
PubMed2006

Detection of platelet-derived growth factor-alpha (PDGF-A) protein in cells of Leydig lineage in the postnatal rat testis.

Platelet-derived growth factor-A (PDGF-A) is a locally produced growth factor in the rat testis secreted by both Sertoli cells and Leydig cells. It has been suggested that PDGF-A may be involved in modulation of testosterone production and may be essential to Leydig cell differentiation, however it is not known at what stage of differentiation PDGF-A begins to be expressed in the cells of Leydig lineage in the postnatal rat testis. Therefore, the objectives of this research were to determine at what postnatal age and in which cell type is PDGF-A first expressed in cells of the adult Leydig cell lineage, and does PDGF-A expression coincide with expression of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), an indicator of steroid hormone synthesis. Male Sprague Dawley rats of postnatal day 1, 7, 9-14, 21, 28, 40, 60, and 90 were used (n=6). Animals were euthanized and their testicles removed, fixed in Bouin's solution, embedded in paraffin, and 5 micrometers sections were prepared. Immunolocalization of PDGF-A and 3beta-HSD was carried out using a peroxidase-streptavidin-biotin method. PDGF-A was first detected in cells of the Leydig cell lineage at postnatal day 10 in progenitor cells, which were surrounding the seminiferous tubules (peritubular). These cells were confirmed to be the progenitor cells and not the mesenchymal or any other spindle-shaped cells in the testis interstitium by immunolocalization of 3beta-HSD and PDGF-A in the cells in adjacent sections of testis tissue from rats of postnatal days 10-14. After postnatal day 10, PDGF-A was continued to be expressed in subsequent cells of the Leydig lineage through day 90 (adult), however, was not present in peritubular mesenchymal precursor cells of the Leydig cell lineage or any other spindle-shaped cells in the testis interstitium at any tested age. These results revealed that PDGF-A first appears in Leydig progenitor cells in the postnatal rat testis at the onset of mesenchymal cell differentiation into progenitor cells at postnatal day 10 and suggest that a functional role(s) of PDGF-A in postnatally differentiated Leydig cells in the rat testis is established at the time of the onset of postnatal Leydig stem cell differentiation. It is suggested that the significance of the first expression of PDGF-A in the Leydig progenitor cells may be associated with inducing cell proliferation and migration of this cell away from the peritubular region during Leydig cell differentiation.

Animals↗
PubMed2006

Altered expression of ZO-1 and ZO-2 in Sertoli cells and loss of blood-testis barrier integrity in testicular carcinoma in situ.

Carcinoma in situ (CIS) is the noninvasive precursor of most human testicular germ cell tumors. In normal seminiferous epithelium, specialized tight junctions between Sertoli cells constitute the major component of the blood-testis barrier. Sertoli cells associated with CIS exhibit impaired maturation status, but their functional significance remains unknown. The aim was to determine whether the blood-testis barrier is morphologically and/or functionally altered. We investigated the expression and distribution pattern of the tight junction proteins zonula occludens (ZO) 1 and 2 in normal seminiferous tubules compared to tubules showing CIS. In normal tubules, ZO-1 and ZO-2 immunostaining was observed at the blood-testis barrier region of adjacent Sertoli cells. Within CIS tubules, ZO-1 and ZO-2 immunoreactivity was reduced at the blood-testis barrier region, but spread to stain the Sertoli cell cytoplasm. Western blot analysis confirmed ZO-1 and ZO-2, and their respective mRNA were shown by RT-PCR. Additionally, we assessed the functional integrity of the blood-testis barrier by lanthanum tracer study. Lanthanum permeated tight junctions in CIS tubules, indicating disruption of the blood-testis barrier. In conclusion, Sertoli cells associated with CIS show an altered distribution of ZO-1 and ZO-2 and lose their blood-testis barrier function.

Adult↗
PubMed1998

Is prolactin a gonadotrophic hormone in red deer (Cervus elaphus)? Pattern of expression of the prolactin receptor gene in the testis and epididymis.

This study investigated the pattern and site of expression of the prolactin receptor gene in the testis and epididymis of red deer collected during the breeding season (n=3). Ribonuclease protection assays using 50 microg total RNA and a 300 bp [32P]-labelled antisense cRNA probe, generated from the extracellular domain of the red deer prolactin receptor, confirmed the expression of the receptor in both the testis and epididymis; a higher level of prolactin receptor mRNA was detected in the epididymis compared with the testis (170.4+/-1.5 x 10(3) and 26.3+/-2.7 x 10(3) arbitrary units respectively; P<0.05). In situ hybridisation using 300 bp [33P]-labelled sense and antisense cRNA probes generated from the extracellular domain of the receptor localised the expression sites to the seminiferous tubules and interstitial compartments of the testis and the epithelial layer of the epididymal duct. Quantification of grain numbers demonstrated a higher level of expression of the receptor in the epididymis compared with the interstitial and seminiferous tubule compartments of the testis (18.1+/-4.4 x 10(2), 10.1+/-2.0 x 10(2) and 8.3+/-0.8 x 10(2) grains/microm2 respectively; P<0.05). However, no differences were detected in the level of expression of the receptor between the interstitial and seminiferous tubule compartments of the testis. Immunocytochemistry using an anti-prolactin receptor antibody, raised against a peptide sequence from the extracellular domain of the rat prolactin receptor, localised expression of the receptor gene to the Leydig cells, pachytene spermatocytes, round spermatids and elongating spermatids. In the epididymis, the receptor was localised to the epithelial layer within the epididymal ducts. Expression of the prolactin receptor gene in the red deer testis and epididymis suggests a role for the hormone in steroidogenesis and spermatogenesis.

Animals↗
PubMed1994

Characterization and localization of oxytocin receptors in the rat testis.

In this study oxytocin (OT) receptors have been characterized and localized in the testis of the rat using the radioiodinated OT receptor antagonist 125I-labelled d(CH2)5 [Tyr(Me)2,Thr4,Tyr9-NH2]-vasotocin (OTA). Receptor density and localization have been compared with the rat testis arginine vasopressin (AVP) receptor using the radioiodinated AVP V1a receptor antagonist 125I-labelled d(CH2)5Sar7-AVP and the radioiodinated linear AVP V1a antagonist 125I-labelled [(C6H5-CH2CO)-O-methyl-D-Tyr-Phe-Gln-Asn-Arg-Pro- Arg-Pro-Arg-Tyr-NH2]. 125I-labelled OTA bound with high affinity to membrane fractions of the rat testis (Ka = 13.8 +/- 1.25 litres/nmol), mammary tissue (Ka = 20.3 +/- 4.36 litres/nmol) and uterus (Ka = 27.8 +/- 0.74 litres/nmol). Competition studies with various OT and AVP receptor agonists and antagonists confirmed that the binding was to OT receptors. AVP receptors in the testis were found to be identical to AVP V1a receptors in the liver. The AVP receptor density in the testis was much higher than the OT receptor density (109 +/- 12.3 vs 5.2 +/- 0.79 (mean +/- S.E.M.) fmol/mg protein). Autoradiographical localization showed that both OT and AVP receptors were present in the interstitial spaces in the testis consistent with binding to Leydig cells. AVP receptors were also localized on the epithelial surfaces of the seminiferous tubules and on testicular blood vessels. This study has, for the first time, found OT receptors in the testis of the rat which have similar ligand-binding characteristics to mammary and uterine OT receptors. The receptor localizations are consistent with binding to Leydig cells.

Animals↗
PubMed1998

Fetal expression of GnRH and GnRH receptor genes in rat testis and ovary.

The identification of gonadal gonadotropin-releasing hormone receptors (GnRH-R) and evidence of direct inhibitory effects of GnRH agonists upon steroidogenesis in adult rat gonads, lend credence to a putative intragonadal role of a locally secreted GnRH or GnRH-like peptide. Using reverse transcription-polymerase chain reaction followed by Southern blot hybridization and sequencing, we identified, both in the ovary and in the testis of fetal and adult rats, a fully processed GnRH messenger RNA (mRNA), the sequence of which, in adult testis, was identical to that found in the hypothalamus. We also detected in the testis, but not in the ovary, a transcript containing the first intron. The ontogeny of GnRH and GnRH-R gene expression was studied in rat gonads from 14.5 to 21.5 days post-coitum (dpc), using dot blot hybridization of total RNA. During this period, the levels of cyclophilin mRNA normalized to total RNA remained unchanged. Thus, we used cyclophilin as an internal standard. GnRH mRNA was detected in the ovary at 18.5 dpc, four days later than in the testis, and similar levels were found in both sexes at birth. GnRH-R mRNA was present at 14.5 dpc in the testis and at 15.5 dpc in the ovary, with the levels at 21.5 dpc being 2.4 times higher in the testis than in the ovary. GnRH and GnRH-R mRNA levels increased in both sexes in late fetal development, but this increase appeared two days sooner in the ovary compared with the testis, thus supporting the hypothesis that expression of the GnRH and GnRH-R genes is regulated in a sex-dependent manner during fetal development. In all cases, expression of GnRH and GnRH-R preceded gonadotropin receptors in the gonads and initiation of gonadotropin secretion by the pituitary.

Animals↗
PubMed2004

Possible expression of functional glutamate transporters in the rat testis.

Neither expression nor functionality is clear in peripheral tissues with the molecular machineries required for excitatory neurotransmitter signaling by L-glutamate (Glu) in the central nervous system, while a recent study has shown that several Glu receptors are functionally expressed in the rat testis. This fact prompted us to explore the possible functional expression in the rat testis of the Glu transporters usually responsible for the regulation of extracellular Glu concentrations in the brain. RT-PCR revealed the expression, in the rat testis, of mRNA for five different subtypes of Glu transporters, in addition to that for particular subtypes of ionotropic and metabotropic Glu receptors. Glutamate transporter-1 (GLT-1) was different in the brain from that in the testis in terms of molecular sizes on Northern and Western blot analyses. In situ hybridization as well as immunohistochemical analysis showed localized expression of glutamate aspartate transporter at interstitial spaces and GLT-1 at elongated spermatids in the rat testis respectively. The expression of mRNA was localized for excitatory amino acid transporter-5 at the basal compartment of the seminiferous tubule in the rat testis. [(3)H]Glu was accumulated in testicular crude mitochondrial fractions in a temperature- and sodium-dependent saturable manner with pharmacological profiles similar to those shown in brain crude mitochondrial fractions. These results suggested that particular subtypes of central Glu transporters for the regulation of extracellular Glu concentrations in the rat testis could be constitutively and functionally expressed.

Amino Acid Transport System X-AG↗
PubMed2005

Endocrine roles of D-aspartic acid in the testis of lizard Podarcis s. sicula.

In the lizard Podarcis s. sicula, a substantial amount of D-aspartate (D-Asp) is endogenous to the testis and shows cyclic changes of activity connected with sex hormone profiles during the annual reproductive phases. Testicular D-Asp content shows a direct correlation with testosterone titres and a reverse correlation with 17beta-estradiol titres. In vivo experiments, consisting of i.p. injections of 2.0 micromol/g body weight of D-Asp or other amino acids, in lizards collected during the three main phases of the reproductive cycle (pre-reproductive, reproductive and post-reproductive period), revealed that the testis can specifically take up and accumulate D-Asp alone. Moreover, this amino acid influences the synthesis of testosterone and 17beta-estradiol in all phases of the cycle. This phenomenon is particularly evident during the pre- and post-reproductive period, when endogenous testosterone levels observed in both testis and plasma were the lowest and 17beta-estradiol concentrations were the highest. D-Asp rapidly induces a fall in 17beta-estradiol and a rise in testosterone at 3 h post-injection in the testis and at 6 h post-injection in the blood. In vitro experiments show that testicular tissue converted L-Asp into D-Asp through an aspartate racemase. D-Asp synthesis was measured in all phases of the cycle, but was significantly higher during the reproductive period with a peak at pH 6.0. The exogenous D-Asp also induces a significant increase in the mitotic activity of the testis at 3 h (P < 0.05) and at 6 h (P < 0.01). Induction of spermatogenesis by D-Asp is recognized by an intense immunoreactivity of the germinal epithelium (spermatogonia and spermatids) for proliferation cell nuclear antigen (PCNA). The effects of D-Asp on the testis appear to be specific since they were not seen in lizards injected with other D- or L-forms of amino acids with known excitatory effects on neurosecretion. Our results suggest a regulatory role for D-Asp in the steroido-genesis and spermatogenesis of the testis of the lizard Podarcis s. sicula.

Amino Acid Isomerases↗
PubMed1985

Preoperative ultrasonography of the undescended testis.

In a prospective study during 1981-1983 42 boys aged 3-12 (mean 6.5) years were operated on for a palpable undescended testis. Twelve boys 3-8 (mean 4) years old were operated on for an unpalpable testis and 2 boys for an ectopic testis. The day before operation an ultrasound examination was performed. Reoperations were made on 11 patients and a bilateral operation on 2. In total, 69 ultrasound examinations were made. Comparison of the position at operation and ultrasound showed accordance in 47 of the 55 cases with only a slight variation of the position in 8 cases. Of the 12 non-palpated testes the ultrasonography showed 4 testicles, 3 non-testis-like formations and no finding in 5 cases. Exploration of these 5 latter cases showed an aplasia testis in 4 and a small intraabdominal testis in 1 boy. Preoperative ultrasonography can be recommended in case of an unpalpable testis in a boy not previously operated on in the inguinal area. Ultrasonography is particularly valuable before reaching a decision on hormonal therapy.

Child↗
PubMedDate not supplied

Depressed DNA synthesis in vitro by early prepubertal undescended human testis.

To study the spermatogenic potential of the early prepubertal inguinal testis and the effect of temperature on spermatogenesis, the levels of incorporation of 3H-thymidine and 14C-uridine into the testicular tissue were studied at 31 degrees C and 37 degrees C in vitro and compared with those of scrotal (descended) testis. 3H-thymidine incorporation into the inguinal testicular tissue at 31 degrees C, which is close to normal testicular temperature, was significantly lower than that of the scrotal testis. There was no significant differences in 14C-uridine incorporation between inguinal and scrotal testis at that temperature. At 37 degrees C, which is close to normal body temperature, 3H-thymidine and 14C-uridine incorporation into the tissues of inguinal and scrotal testes was significantly higher than at 31 degrees C. It would appear that DNA synthesis of the inguinal testis is lower than that of the scrotal testis at 31 degrees C, and higher temperature, at least for a short while, did not contribute to the impairment of spermatogenic potential in early prepubertal inguinal testis.

Adolescent↗
PubMed2005

Expression of mucin genes in the human testis and its relationship to spermatogenesis.

In this study we investigate the expression pattern of mucin genes in the human testis and evaluate the relationship between the expression of mucin genes and impaired spermatogenesis in the human testis. Thirty human testis tissues were collected from patients undergoing diagnostic testicular biopsy to investigate the cause of infertility. One part of the tissue underwent histological observation, and the other part of the tissue was subjected to semiquantitative RT-PCR of mucin genes, that is, mucin1, 2, 3, 4, and 9. The relative amount of mucin mRNAs was calculated by densitometry using glyceraldehydes-3-phosphate dehydrogenase (GAPDH) as an internal control. The samples were histologically diagnosed as either obstructive azoospermia with normal spermatogenesis (n = 13) or non-obstructive azoospermia with impaired spermatogenesis (n = 17). In the human testis with normal spermatogenesis, mRNA expression of mucin1, 9, 13 and GAPDH were found, but RT-PCR products of mucin 2, 3 and 4 were not detected. In the testis with impaired spermatogenesis, however, RT-PCR product of mucin1 was not found. There was no difference in the other mucin mRNA expression patterns between the testis with either normal or impaired spermatogenesis. To our knowledge, this study is the first that has detected the mRNA of mucin9 and 13 in human testis. This study also shows that mucin1 expression might be closely related to spermatogenesis. Our findings should be substantiated by more direct evidence, such as mucin protein expression and localization.

Adult↗
PubMed1999

[Traumatic dislocation of the testis. Report of three cases].

The authors report three cases of traumatic dislocation of the testis. Each case concerned a young patient, victim of a motorbike accident with direct trauma to the perineum and scrotum on the reservoir. Preoperative radiological assessment consisted of ultrasound, computed tomography, or even magnetic resonance imaging, depending on the case. Surgical exploration revealed 3 traumatic dislocations of the testis, including one with associated torsion of the spermatic cord. One case also presented fracture of the contralateral testis, which was not dislocated. Each case was repaired by repositioning of the testis in the scrotum. The fractured testis could not be preserved. A review of the literature confirmed the rarity of these traumatic lesions. Dislocations are usually inguinal, sometimes bilateral, and can be ectopic. Spermatic cord lesions may also be associated. The authors define the place of radiological assessment, which can guide the diagnosis and therapeutic strategy. Surgical exploration, allowing assessment of the lesions, is required in every case. Repositioning of the testis in the scrotum ensures cure when the testis is still viable.

Accidents, Traffic↗