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Testis biopsy findings in the spinal cord injured patient.

PURPOSE: Azoospermia after electroejaculation in spinal cord injured men may be due to testicular failure or obstruction. These men can initiate pregnancy with assisted reproductive techniques, such as intracytoplasmic sperm injection, but only if sperm are present in the testis biopsy. We analyzed the histopathology of testis biopsies from spinal cord injured men and assessed whether patient factors were predictive of testis biopsy pathology. MATERIALS AND METHODS: A total of 50 paraplegic men undergoing testis biopsy were divided into 2 groups based on normal or abnormal testis histopathology. Patient age, post-injury years, level of lesion, hormonal status and semen analysis results were compared. RESULTS: Spermatogenesis was normal in 28 of the 50 patients. Hypospermatogenesis was exhibited in 15, maturation arrest at the spermatid stage in 6 and maturation arrest at the spermatocyte stage in 1 of the 22 abnormal cases. Nevertheless, mature sperm were identified in 43 of 50 biopsies (normal spermatogenesis and hypospermatogenesis). Men with normal spermatogenesis had better forward progression of sperm and a higher testosterone-to-luteinizing hormone ratio. Otherwise, there was no statistically significant correlation between study variables and testis biopsy results. No factors were predictive of testis biopsy histopathology. CONCLUSIONS: The documentation of mature sperm in 43 of 50 biopsies from spinal cord injured patients suggests that a high rate of sperm retrieval is possible using testicular sperm extraction if sperm cannot be retrieved from the ejaculate. With intracytoplasmic sperm injection techniques the majority of spinal cord injured men retain fertility potential, even if azoospermic following electroejaculation.

Adult↗

Shedding of somatic angiotensin-converting enzyme (ACE) is inefficient compared with testis ACE despite cleavage at identical stalk sites.

The somatic and testis isoforms of angiotensin-converting enzyme (ACE) are both C-terminally anchored ectoproteins that are shed by an unidentified secretase. Although testis and somatic ACE both share the same stalk and membrane domains the latter was reported to be shed inefficiently compared with testis ACE, and this was ascribed to cleavage at an alternative site [Beldent, Michaud, Bonnefoy, Chauvet and Corvol (1995) J. Biol. Chem. 270, 28962-28969]. These differences constitute a useful model system of the regulation and substrate preferences of the ACE secretase, and hence we investigated this further. In transfected Chinese hamster ovary cells, human somatic ACE (hsACE) was indeed shed less efficiently than human testis ACE, and shedding of somatic ACE responded poorly to phorbol ester activation. However, using several analytical techniques, we found no evidence that the somatic ACE cleavage site differed from that characterized in testis ACE. First, anti-peptide antibodies raised to specific sequences on either side of the reported cleavage site (Arg(1137)/Leu(1138)) clearly recognized soluble porcine somatic ACE, indicating that cleavage was C-terminal to Arg(1137). Second, a competitive ELISA gave superimposable curves for porcine plasma ACE, secretase-cleaved porcine somatic ACE (eACE), and trypsin-cleaved ACE, suggesting similar C-terminal sequences. Third, mass-spectral analyses of digests of released soluble hsACE or of eACE enabled precise assignments of the C-termini, in each case to Arg(1203). These data indicated that soluble human and porcine somatic ACE, whether generated in vivo or in vitro, have C-termini consistent with cleavage at a single site, the Arg(1203)/Ser(1204) bond, identical with the Arg(627)/Ser(628) site in testis ACE. In conclusion, the inefficient release of somatic ACE is not due to cleavage at an alternative stalk site, but instead supports the hypothesis that the testis ACE ectodomain contains a motif that activates shedding, which is occluded by the additional domain found in somatic ACE.

Amino Acid Sequence↗

Formation of 5alpha-reduced C19 steroids from progesterone in vivo by 5alpha-reduced pathway in older prepubertal rat testis.

Either [3H] progesterone (0.5 or 5 nmol/5 muCi), 5alpha-[3H] pregnane-3,20-dione (5 nmol/5 muCi) or [14C] progesterone (6.6 nmol/0.2 muCi) plus 5alpha-[3H]-pregnane-3,20-dione (1 or 6.6 nmol/0.6 muCi), suspended in 0.05 ml of physiological saline solution, was injected into each testis of 32- and 90-day-old rats. Following injection, radioactive metabolites in testis and spermatic vein blood were extracted, isolated, measured and identified by column and paper chromatographies, with derivative formation and recrystallization to constant specific activity. In the blood and testis of older prepubertal rats, major 17-OH-C21 and C19 metabolites of progesterone were 5alpha-reduced steroids such as 3alpha, 17alpha-dihydroxy-5alpha-pregnan-20-one, 5alpha-androstane-3alpha,17beta-diol and androsterone. Following injection of [14C] progesterone plus 5alpha-[3H] pregnane-3,20-dione into 32-day-old rat testis, no significant augmentation of the isotope from progesterone was observed in 5alpha-reduced C19 steroids as compared with 5alpha-reduced 17-OH-C21 steroids, indicating that 5alpha-reduced C19 steroids were mainly formed from 5alpha-reduced 17-OH-C21 steroids in older prepubertal testis. In the blood and testis of adult rats, small amounts of 5alpha-reduced metabolites were shown to be produced from progesterone, while active 17alpha-hydroxylation of 5alpha-pregnane-3,20-dione followed by C17-C20-lyase reaction was demonstrated. These findings seem to indicate that formation of 5alpha-reduced C19 steroids from progesterone by the 5alpha-reduced pathway is a major pathway of androgen biosynthesis in older prepubertal rat testis in vivo.

Animals↗

[Expression of thyrotropin-releasing hormone receptor mRNA in the rat testis development].

In order to investigate the regulation of thyrotrophin-releasing hormone receptor (TRH-R) expression in rat testis, and to study their function in spermatogenesis, oligonucleotide primers were designed from the sequences of rat pituitary TRH-R cDNA for reverse transcription-polymerase chain reaction (RT-PCR). Specific fragments of TRH-R cDNA were cloned. DNA sequence analysis indicated that cDNA sequence of TRH-R from rat testis was consistent with those of pituitary TRH-R cDNA. The non-radioactive in situ hybridization (NR-ISH) technique was applied to localize cells encoding TRH-R mRNA in the rat testis. Hybridization signals were detected exclusively in the leydig cells, but not in the spermatogenetic cells of the rat testis. TRH-R mRNA in the testis was quantitated in RNA samples prepared from rats at different developmental stages by real time quantitative RT-PCR. The quantitative analyses demonstrated that no TRH mRNA could be detected at the earliest stage (day 8). TRH mRNA signals were detected on day 15 and increased progressively on day 20, 35, 60 and 90. These results suggested that rat testis could specifically express TRH-R, and the transcription of TRH-R gene in the rat testis was development-dependent.

Animals↗

[Molecular cloning for testis spermatogenesis cell apoptosis related gene TSARG1 and Mtsarg1 and expression analysis for Mtsarg1 gene].

Spermatogenesis cell apoptosis is a very complex process, which needs many molecules to take part in the programmable death of cells in testis. At present, research of apoptosis for spermatogenesis cell is at the primary step. It is very important to clone spermatogenesis cell apoptosis related genes and spermatogenesis genes in testis. Applying the bioinformatics and experiment technique, we have cloned human and mouse novel gene cDNA sequences--human testis and spermatogenesis cell apoptosis related gene 1 (TSARG1) and mouse testis and spermatogenesis cell apoptosis related gene 1(Mtsarg1) from human and mouse testis cDNA library respectively, using a cDNA fragment (GenBank accession number: BE644538) as an electronic probe, which was significantly changed in expression in cryptorchidism. The GeneBank accession numbers of Mtsarg1 and TSARG1 are AF399971 and AY032925 (NM_139073), respectively. The Mtsarg1 has a 55% identity and 61% similarity with TSARG1 at the amino acid level, which did not share significant homology with any other known protein in databases. The full-length cDNA of TSARG1 gene is 973 bp, including 549 bp open reading frame(ORF) and coding 183 amino acids, whereas the full-length cDNA of Mtsarg1 gene is 1103 bp, including 576 bp ORF and coding 192 amino acids. The predicted molecule weight of TSARG1 is 19948.61 Dolton, and the deduced iso-electric point is 10.24, whereas the Mtsarg1 is 20875.93 and is 9.83, being alkaline proteins. RT-PCR analysis showed that Mtsarg1 was expressed significantly in testis and faintly in epididymis in the ten tissues of testis, ovary, spleen, kidney, lung, heart, brain, epididymis, liver and skeletal muscle in mouse, while it wasn't expressed in the other eight tissues. Therefore, our results suggested that Mtsarg1 and TSARG1 would be pay potential roles in spermatogenesis cell apoptosis or spermatogenesis.

Amino Acid Sequence↗

The effect of prophylactic melatonin administration on reperfusion damage in experimental testis ischemia-reperfusion.

AIM: Torsion of testis, which is a urologic emergency case, is generally treated by surgical detorsion procedure. However, the resulting reperfusion and both ipsilateral and contralateral testis damage caused thereby are important problems. This study aims at investigating the administration of prophylactic melatonin in order to reduce free radical damage that is caused due to reperfusion after experimental testis torsion-detorsion procedure. MATERIAL AND METHOD: The rats used in the study were allocated to four groups, each containing 10 rats. Rats in Group I had six hours of torsion (ischemia) followed by orchiectomy. Rats in Group II had six hours of torsion, then received melatonin (10 mg/kg/IM) and after that had detorsion (reperfusion). Rats in Group III had detorsion after six hours of torsion and serum physiologic administration (the same volume as melatonin). Torsion and/or detorsion procedures were not applied in Group IV (control). Ipsilateral, contralateral testis and plasma Malondialdehyde (MDA) levels were determined in all groups. RESULTS: Tissue and plasma MDA levels in the group which had detorsion were found to be significantly higher than those in the group that had orchiectomy only (p<0.02). Ipsilateral and contralateral testis MDA levels were identified to be significantly lower in the group receiving prophylactic melatonin in comparison to the group receiving serum physiologic (p<0.02). Plasma and contralateral MDA levels correlated positively with MDA levels identified in ipsilateral testis in all groups (rs=+0.89, n=40, p=0.000). CONCLUSION: In cases where testis torsion is identified, administration of melatonin just before torsion may reduce local and systemic free radical damage.

Animals↗

Identification of glutamate transporters and receptors in mouse testis.

AIM: To investigate the presence of glutamate transporters and receptors in mouse testis. METHODS: Glutamate uptake analysis was performed to study the function of glutamate transporters in mouse testis. Comparative RT-PCR technique and sequencing analysis were used to study the expression of glutamate receptors and transporters in mouse testis. RESULTS: Mouse testis possessed glutamate uptake capacity with sodium-dependence. Vmax value of glutamate uptake was (1.60 +/- 0.21) pmol/min per mg protein and Km value of glutamate uptake was (11.0+/-1.6) micromol/L in mouse testis according to saturation analysis. Furthermore, the uptake activity could be inhibited by DHK (GLT1 selective inhibitor) and THA (glutamate uptake inhibitor). In addition, RT-PCR results revealed that glutamate transporters (GLT1 and EAAC1) and ionotropic glutamate receptors (NR1, NR2B, GluR6 and KA2) were expressed in mouse testis. CONCLUSION: Glutamate transporters and receptors do exist in mouse testis.

Amino Acid Transport System X-AG↗

The oligosaccharidic content of the glycoconjugates of the prepubertal descended and undescended testis: lectin histochemical study.

The saccharidic content of the glycoconjugates has been studied in the descended the undescended testes of a 8 years old boy. For this purpose, a battery of seven HRP-conjugated lectins (SBA, DBA,PNA,WGA,UEAI, LTA and ConA) was used. D-galactose-N-acetyl-D-galactosamine and alpha-L-fucose sugar residues, which were present in the cytoplasm of the Sertoli cells of the normally positioned prepubertal testis, were not detected in the same cells of the undescended testis. The Leydig's cells of the descended testis appeared characterized by N-acetyl-D-glucosamine which was absent in the rare and atrophic Leydig's cells of the cryptorchid testis. Differences in sugar residues distribution between the descended and the undescended testis were also detected in the lamina propria of the seminiferous tubules. Peritubular myoid cells in the undescended testis only reacted with PNA, after neuraminidase digestion, thus revealing the presence of D-galactose (beta1-->3)-N-acetyl-D-galactosamine and sialic acid. In this study a complete distributional map of the sugar residues of the glycoconjugates in the descended and undescended prepubertal testis is reported.

Child↗

[Transplantation of mouse bone marrow mesenchymal stem cells into the xenogeneic testis].

OBJECTIVE: To study transplantation of mouse bone marrow mesenchymal stem cells (MSCs) into the xenogeneic testis. METHODS: (1) The tibias and femurs were dissected from 5-6-week-old mice. The marrow in the tibias and femurs was flushed out with medium. MSCs were isolated, cultured and purified in vitro by Percoll density gradient centrifugation combined with adherent method. (2) MSCs of the third generation were adopted and marked with Hoechest33342 for observation, and then made into cell-suspending fluid. (3) The marked MSCs were transplanted into the testis of the xenogeneic mouse by testis net injection. The biopsies of the testis tissues were carried out at different time and made into frost slices at three sites for observation. RESULTS: (1) A lot of purified MSCs were obtained at the third generation. (2) The nucleoli of the marked MSCs showed light-yellow under the fluoroscope. (3) Xenogeneic transplantation of mouse bone marrow MSCs by testis net injection was successful, without immunoreaction. On the 1 st day after transplantation, MSCs only concentratively distributed in the medial slices, the nucleoli being light-yellow; On the 1 st and 3 rd day, MSCs dispersively distributed in the medial slices; On the 6th, 9th and 12th day, MSCs presented in all the slices of the three sites, some ranging tubally; On the 15th and 18th day, the fluorescence of MSCs weakened; On the 21 st day, the fluorescence of MSCs disappeared. CONCLUSION: Transplantation of mouse bone marrow MSCs into the xenogeneic testis by testis net injection is effective and feasible, without immunoreaction. MSCs can survive after transplantation.

Animals↗

Radioimmunoassay for testicular cytochrome c (ct). Evidence for the presence of apocytochrome ct pool in rat testis extract.

Mammalian testis contains a tissue-specific testicular cytochrome c (cyt ct). By immunizing rabbits with rat cyt ct and phosphorylated albumin (pBSA), rabbit anti-cyt ct was produced. Then the antiserum was applied to phosphorylated bovine serum albumin and rat somatic cyt c (cs)-Sepharose affinity columns to remove cross-reacting antibodies. The resultant anti-cyt ct was highly specific for cyt ct. From immunoblot assays, no protein other than cyt ct in rat testis extract was bound by the anti-cyt ct. By using the anti-cyt ct, radioimmunoassay (RIA) was developed for the quantitation of cyt ct in rat testis extract. The observation that the RIA did not bind rat cyt cs (1-1000 pmol), and other rat tissue extracts (kidney, heart, lung) further indicated that the RIA was highly specific for rat cyt ct. Separately, the concentration of holocyt ct was determined using CM-cellulose chromatography and subsequent spectral analysis on the same testis extract. The total cyt ct concentration in the rat testis extract determined by the RIA was about 3-fold higher than those determined by the latter techniques. Since the affinity purified anti-horse cyt c cross-reacted with both horse holo- and apocyt c, anti-rat cyt ct will cross-react with rat apocyt ct. Thus the concentration of cyt ct quantitated by the polyclonal anti-cyt ct-based RIA probably included apocyt ct concentration as well. Therefore, the higher cyt ct concentration determined by the RIA was probably attributed to the presence of the apocyt ct in the testis extract. The presence of the high concentration of the apocyt ct pool in testis is probably necessary to maintain continuous spermatogenesis, during which holocyt ct is incorporated into sperm mitochondria.

Animals↗

[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↗

Biochemical observations on the protein and nucleic acid metabolism of the rat testis and epididymis after treatment with low doses of alpha-chlorohydrin.

A biochemical study was made on the effects of low doses of alpha-chlorohydrin on the protein and nucleic acid metabolism of the rat testis and epididymis. RNA and protein levels were decreased both in the testis and epididymis. The DNA content of the testis and epididymis did not change after exposure of the animals to the drug. The reduced concentrations of RNA and protein were closely paralleled by the increased activity of proteinase (protein hydrolyzing enzyme) and ribonuclease (RNA degrading enzyme) in the testis and epididymis. The gamma-glutamyl transpeptidase activity of both the testis and epididymis was also reduced indicating the slow transfer of amino acids across the cell membranes of testis and epididymis and thus low protein synthesis. The DNAase levels of rat testis and epididymis did not show any appreciable change in response to the alpha-chlorohydrin treatment. These studies indicate that although there may not be any histological damage in the tissue the metabolic pathways may become defective much earlier before any visible morphological change is discernible.

Animals↗

[Nonpalpable testis: current diagnostic and therapeutic trends].

Management of the nonpalpable testis often represent a significant diagnostic and therapeutic challenge for the pediatric surgeon. A variety of imaging studies may locate nonpalpable testis and include ultrasound, CT, MRI, gonadal vasography, and herniography, but none is completely reliable in locating a gonad or proving its absence. Laparoscopy has the advantage of great reliability in locating testes or proving their absence and can be coupled with surgical management; the laparoscopic findings determine the subsequent operative steps. Accurate knowledge of testis location facilitates development of an appropriate surgical strategy either laparoscopic or laparoscopic-assisted or open procedure. The Authors report their preliminary experience with laparoscopy in 30 patients (age range 2-5 years) with 34 nonpalpable testes: 18 testes were intraabdominal, 7 canalicular, 9 atrophic or absent. Out of the 18 intraabdominal testes 2 patients underwent orchiectomy (very small testes), 1 patient testis detorsion and 15 internal spermatic vessels clipping and cutting (first step of staging Fowler-Stephens orchidopexy). At the moment 8 patients, after a 8-10 months interval, underwent second staged vas-based orchidopexy with good results as judged by size and throphism of the relocated testes. An inguinal exploration has been made in 7 patients: 4 orchiectomy (hypo-atrophic testis), 3 standard orchidopexy. In 9 patients the testis were absent. In order to have a good-sized adolescent scrotal pouch, insertion of an infant-size testicular prosthesis is recommended for children with a vanishing or absent testis, if the parents agree.

Algorithms↗

Testis-specific transcription start site in the aspartate aminotransferase housekeeping gene promoter.

We have studied the expression and regulation of the rat testis cytosolic aspartate aminotransferase gene. The cytosolic aspartate aminotransferase activity was 5-fold lower in the testis than in the liver and kidney. A 1.9-kilobase mRNA form was detected in the rat testis in contrast to the 2.1- and 1.8-kilobase forms present in other organs. Using Northern blot and S1 mapping analyses, we found that the proximal polyadenylation site was almost exclusively used in the testis as opposed to other organs where the distal site was preferentially used. RNase protection and primer extension analysis showed that transcription was initiated at multiple sites in all organs, but the pattern of those start sites was different in the testis; in particular, a novel transcription start site was specifically detected in this organ (at position -115 from the translation start site). This site was first observed in 29-day-old rats and was maximally utilized in the adult testis. DNase I footprinting using testis nuclear extracts revealed the presence of three sites of DNA-protein interaction in the 250-base pair proximal promoter, a pattern similar to the one found using liver nuclear extracts. However, the proteins bound had different properties as shown by gel retardation experiments. We conclude that the pattern of transcription initiation and the polyadenylation site selection of a housekeeping gene can be tissue-specific.

Animals↗

Glycolipid composition of human testis at different ages and the stereochemical configuration of seminolipid.

1. The sterochemical configuration of glycerol moiety of seminolipid (1-O-alkyl-2-O-beta-D-(3'-sulfo) galactopyranosylglycerol: Ishizuka, I., Suzuki, A. and Yamakawa, T. (1973). J. Biochem. 73, 77--87) from mammalian testis was determined by measurement of optical rotatory dispersion of alkylglyceryl ether moiety, establishing the final structure of the major glycolipid from mature testis of mammals as 1-O-alkyl-2-O-beta-D-(3'-sulfo)-galactopyranosyl-sn-glycerol. 2. The simple and sensitive modification of fluorometric determination of galactolipids and sphingolipids was described. This method does not require lipid extraction from silica gel of thin-layer chromatography, and allows a quantitative assessment of the sphingoglycolipids and galactosyl glycerides using a small amount of testicular tissue. 3. Various lipid classes from human testis of varying age groups were compared. The total lipid and seminolipid content was highest in adult (40-years-old) testis amounting to 39.0 mg and 158.7 nmol/g tissue, respectively. Seminolipid was not detected in infant (2 years old) or child (9 years old) and found only at the concentration of 25.3 nmol/g in the testis of aged (60--90 years of age) supporting the postulated relation of seminolipid with spermatogenesis and sexual activity. In contrast, ganglioside content was highest in the testis of aged probably reflecting fibrosis of the testis. The main ganglioside was found to be hematoside with N-acetylneuraminic acid. Gangliosides Gm1 and GD1a were also detected.

Adult↗

Temporal patterns of A-myb and B-myb gene expression during testis development.

We recently reported the cloning and sequencing of the mouse A-myb proto-oncogene cDNA and the abundant expression of this mRNA primarily in the testis of adult mice. The A-myb mRNA is detectable by in situ hybridization specifically in the spermatogenic cells, and is downregulated during terminal differentiation. A low level of expression is observed in a few other tissues, including ovary, spleen and brain. We have extended those studies by examining A-myb and B-myb expression during testis development in the mouse. The A-myb and B-myb genes are both expressed in a cell- and stage-specific manner during testis development. The B-myb mRNA is expressed most highly in gonocytes of the fetal testis and in spermatogonia and early spermatocytes in the adult. B-myb expression decreases at day 18 post partum, coincident with the initial appearance of late pachytene spermatocytes. B-myb expression was also detectable in some interstitial cells of the fetal and adult testis. The A-myb mRNA was not detectable by in situ hybridization in fetal day 15.5 gonocytes but was detectable at a low abundance by RT-PCR in fetal and newborn mice. A-myb mRNA expression increased at post-natal day 10, when primary spermatocytes first appear. In the adult, the A-myb mRNA was expressed highly in a sub-population of spermatogonia and in primary spermatocytes, but was not detectable in spermatids. This expression of A-myb is consistent with the meiotic arrest that is observed in A-myb-deficient male mice. We conclude that B-myb may play a critical role in controlling the proliferation or differentiation of gonocytes and spermatogonia and possibly the somatic lineages as well, whereas A-myb is required for progression through the first meiotic prophase. These distinct roles for B-myb and A-myb during spermatogenesis may reflect distinct transactivation potentials of the two proteins. Further studies to determine the functions of A-myb and B-myb in the developing testis should improve our understanding of the molecular events associated with spermatogenesis and differentiation of the Sertoli and other somatic cell types of the testis.

Animals↗

Transplantation of testis germinal cells into mouse seminiferous tubules.

In the adult male, germ cell differentiation takes place in the seminiferous tubules of the testis by a complex, highly organized and very efficient process. A population of diploid stem-cell spermatogonia that lie on the basement membrane of the tubule continuously undergoes self-renewal and produces progeny cells, which initiate the process of cellular differentiation to generate mature spermatozoa. Each testis contains many seminiferous tubules, which are connected at both ends to a collecting system called the rete testis. The mature spermatozoa pass from the tubules into the rete and are then carried through efferent ducts to the epididymis for final maturation before they are ready to fertilize an egg. In previous studies, we have demonstrated that donor testis cells collected from a fertile mouse are able to generate spermatogenesis when transplanted to the seminiferous tubules of an infertile male. The spermatozoa produced by the recipient from the donor-derived spermatogonial stem cells are able to fertilize eggs and produce progeny carrying the donor male haplotype. Furthermore, donor testis stem cells from a rat will generate normal rat spermatozoa following transplantation to a mouse testis. The spermatogonial transplantation technique is clearly valuable and applicable to many species, but it is difficult. Therefore, several procedures to introduce donor cells into the seminiferous tubules of a recipient have been developed using the mouse as a model, and they are described here in detail. The results indicate that microinjection of cell suspensions into the seminiferous tubules, efferent ducts or rete testis are equally effective in generating donor cell-derived spermatogenesis in recipients. Each approach is likely to be useful for different experimental purposes in a variety of species.

Animals↗

Characterization and developmental expression of a testis-specific adenosine deaminase mRNA in the mouse.

Adenosine is able to alter intracellular cAMP levels and to affect the physiological functions of sperm. It also modulates FSH action through its Gi protein coupled receptors. Adenosine deaminase (ADA), an enzyme regulating adenosine levels, exists in the plasma membrane of the sperm, but little is known about its action on testicular function. The present study investigates the expression of a testis-specific ADA mRNA with development and in comparison to several other tissues in the mouse. In addition, the sequence of a testis-specific ADA cDNA was determined from an adult mouse testis library. We demonstrate for the first time the presence of a major 1,350 bp testis-specific ADA mRNA and a weaker 1,200 bp ADA transcript whose developmental expression starts on day 28 of life. Sequence analysis of the testis-specific ADA cDNA indicated that exons 1 and 2, as well as the first 8 nucleotides of exon 3 of the somatic cell ADA cDNA were absent in the testicular ADA cDNA. The deduced open reading frame of the testis-specific ADA cDNA indicates absence of the first 51 amino acids at the 5' end that are present in the somatic cell ADA protein. The developmental onset of expression of the testis-specific ADA mRNA may be related to specific proliferation/differentiation events of spermatogenesis.

Adenosine Deaminase↗