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At least 685 records · Page 38Linked to original sources
PubMed2003

Isoforms of angiotensin I-converting enzyme in the development and differentiation of human testis and epididymis.

Angiotensin I-converting enzyme (ACE; CD143, Kininase II, EC 3.4.15.1) is known to be crucial for male fertility in animal models. We therefore studied its testicular (tACE) and somatic (sACE) isoforms in foetal and adult human testis and epididymis using monoclonal antibodies and cRNA probes. During spermatogenesis, tACE was found only in differentiating germ cells and was the only isoform within the seminiferous tubules of adult men. Although tACE mRNA was present in spermatocytes, tACE protein was initially found in post-meiotic step 3 spermatids and increased markedly during further differentiation. The enzyme was strictly confined to the adluminal membrane site of elongating spermatids and was localized at the neck and midpiece region of released and ejaculated spermatozoa. In contrast, sACE was expressed heterogeneously in Leydig cells and endothelial cells of the testicular interstitium, and homogeneously along the luminal surface of epithelial cells lining the ductuli efferents, corpus and cauda of epididymis, and vas deferens. The cell- and site-restricted pattern of sACE corresponded to that found in foetal tissues except an additional and transient expression of sACE in foetal germ cells and foetal Sertoli cells. Our study documents for the first time in humans the regulation and unique cellular distribution of ACE isoforms during the ontogenesis of the lower male genital tract.

Aging↗
PubMed1986

The effect of changing the distance between the TATA-box and cap site by up to three base pairs on the selection of the transcriptional start site of a cloned eukaryotic gene in vitro and in vivo.

We have studied how small changes in the distance between the TATA-box and cap site affect transcription of a eukaryotic gene in vitro and in vivo. The trout protamine gene TPG-3 [Gregory et al. (1982) Nucl. Acids Res. 10, 7581-7592] is a good model for such a study as it has (i) a consensus TATA-box 32 base pairs (bp) upstream from an A-residue which is the natural cap site (designated +1) (ii) two further A-residues at -5 and +5, providing alternative transcriptional start sites which are in significantly different sequence environments and (iii) a unique AvaII restriction site immediately downstream from the TATA-box which is ideal for the insertion or deletion of up to 3bp. Transcripts of the wild type and mutant genes were generated in vitro using a HeLa whole cell extract or 'in vivo' by transient expression following their transfection into HeLa cells. These 'spacer' mutations did not affect the efficiency of transcription of the gene in vitro but they did affect the selection of transcriptional start site both in vitro and 'in vivo'. Analysis of 5'-ends by S1-mapping and primer extension showed that the A-residue(s) selected are those which, by insertion or deletion, come to lie on the same face of the DNA double helix as the TATA-box, although the DNA sequence in the immediate vicinity of the potential start sites influences their utilisation. Comparison of the TPG-3 wild type transcripts in these experimental systems with natural mRNA suggests that cap site selection is more stringent in the developing trout testis.

Animals↗
PubMed1991

Determining transcript number using the polymerase chain reaction: Pgk-2, mP2, and PGK-2 transgene mRNA levels during spermatogenesis.

We describe a technique that uses reverse transcription and the polymerase chain reaction (pcr) to rapidly quantitate numbers of specific mRNA transcripts from nanogram quantities of total cellular RNA. Linearity of input molecules to output signal was maintained by limiting the cycle number and the amount of input RNA and by minimizing the number of manipulations. Absolute levels of specific transcripts were determined by the inclusion of a separate standard curve composed of serially diluted in vitro transcribed RNA run alongside the experimental samples. This allowed rapid quantitation of many samples simultaneously. We applied this technique to measuring the expression of phosphoglycerate kinase 2 (Pgk-2) transgenes in the mouse testis during development. A human PGK-2 transgene, a PGK-2/CAT transgene, and the endogenous mPgk-2 gene all displayed similar patterns and levels of expression, consistent with the conclusion that peak RNA accumulation occurs in pachytene spermatocytes. Mouse protamine 2 (mP2) is expressed at a level approximately tenfold higher than Pgk-2 and displays a different pattern of expression consistent with initiation of transcription occurring in haploid round spermatids.

Animals↗
PubMed2004

Estradiol-17beta induced a reversible sex change in the fingerlings of protandrous black porgy, Acanthopagrus schlegeli Bleeker: the possible roles of luteinizing hormone in sex change.

The objectives of the present study were to investigate the effects of oral administration of estradiol-17beta (E(2)) on luteinizing hormone (LH) in plasma, aromatase activity in gonad, and sex change in the fingerlings of protandrous black porgy, Acanthopagus schlegeli Bleeker. The expression of estrogen receptor (ER) and androgen receptor (AR) transcripts in gonad was also analyzed. Undifferentiated (2-mo-old) black porgy were divided into two groups, one fed a control diet and the other a diet mixed with E(2) (6.0 mg/kg feed) for 5 mo. Fish treated with E(2) for 3 mo showed complete suppression of spermatogenesis and spermiation and induced sex change with primary oocytes. Aromatase activity in forebrain and midbrain was increased in the control in December-March (during the spawning season). E(2) stimulated aromatase activity in the brain. Higher gonadal aromatase activity in concordance with elevated levels of plasma LH was observed in the E(2) group compared with the control. After 2-mo of E(2) termination, regressed testicular tissue recovered and controlled females gradually reversed back to functional males in January and March. Plasma LH levels were higher in the E(2)-terminated group during the period of reversible sex change (from a controlled female to male) compared with the control. The expression of ER and AR transcripts was closely related to the development of testis and ovary. The data showed that E(2) induced a reversible sex change with high plasma LH. Increase of gonadal aromatase and decrease of ER/AR were associated with controlled sex change. Plasma LH levels were correlated with the conversion from a controlled female to male in black porgy.

Animals↗
PubMed1987

Development of the blood-testis barrier in the domestic fowl (Gallus domesticus).

The formation of the blood-testis barrier (BTB) in the domestic fowl was studied at the electronmicroscopic level employing lanthanum as a tracer. No effective barrier could be demonstrated in testes before puberty, although several components of the Sertoli junctional complex such as focal tight junctions and desmosomes were already existent. The time of onset of meiosis after hatching showed great individual variation and meiosis did not occur synchronously in the tubules of a given testis. An effective barrier could first be detected in tubules containing early spermatids, and in which spermatogonia and primary spermatocytes at the leptotene stage were still within the open compartment. Thus, barrier formation was correlated with the occurrence of haploid germ cells. Complete compartmentation of seminiferous tubules, leaving only spermatogonia within the open compartment, was attained in tubules containing elongated spermatids of the maturation phase. In these tubules, primary spermatocytes at the leptotene stage were situated in an intermediate compartment.

Animals↗
PubMed1961

Effect of reserpine on growth and sexual development of chickens.

One-month-old male chickens were given injections of 1 mg, 2 mg and 4 mg/kg of reserpine. The injections were repeated at weekly intervals for three months. The chickens receiving reserpine grew at half the rate of untreated control chickens and failed to grow combs. At 4 months of age the testes of reserpine-treated chickens were only about one-tenth the weight of the testes of the control chickens and histologically they showed extreme hypoplasia of the seminiferous tubules. Two large doses of reserpine one month apart could cause atrophy of the testes of adult roosters.

Animals↗
PubMed1980

Serum spermagglutinins and semen quality in the bull.

Three bulls injected with homologous semen or testis material developed spermagglutinins in serum while one control bull inoculated with egg white did not. In one bull a high spermagglutinin titre was associated with allergic epididymitis, a decreased proportion of motile spermatozoa, and an increased proportion of tall abnormalities. The palpable lesion persisted for 35 days, the spermagglutinin titre and semen abnormalities for a further 2 months. No change in semen quality was associated with the lower serum spermagglutinin titres in the other two treatment bulls or over comparable periods of time in the control bull. No naturally occurring spermagglutinins were found in a population of 50 bulls with varying semen qualities at an artificial breeding centre.

Agglutinins↗
PubMed1991

Proliferative activity of gonocytes, Sertoli cells and interstitial cells during testicular development in mice.

Developing mouse testis was studied from Day 14 post coitum (p.c.) until Day 35 post partum (p.p.) by [3H]thymidine autoradiography. The gonocytes proliferated actively at Day 14 p.c., the [3H]thymidine labelling index (L.I.) being 7.5%, and were quiescent from Day 16 p.c. up to the first day of life, when spermatogenesis started. The L.I. increased to 20% at Day 2 p.p. The L.I. for the Sertoli cells was approximately 20% before birth. After birth the proliferative activity decreased. After Day 11 p.p., the Sertoli cells showed their typical adult appearance. After Day 17 p.p. no labelled Sertoli cells were observed. The Leydig cells featured a very low proliferative activity up to Day 21 p.p. (L.I. of maximal 1.9%). At Day 29 p.p. there was a peak of 7.4% in L.I., followed by a sharp decrease to 0.35% at Day 35 p.p. The L.I. of mesenchymal cells decreased from 11.4% at Day 14 p.c. to 1.1% at Day 14 p.p. and remained more or less constant thereafter. The proliferative activity of myoid, endothelial and perivascular cells followed a similar course to that of mesenchymal cells, their L.I.s being high before birth (16, 12.5 and 19%, respectively, decreasing until Day 14 p.p. (0.6, 2.0 and 1.2%, respectively) and thereafter being more or less constant. There was an increase in the relative number of Leydig cells from approximately 4% of the total interstitial cell number at Day 14 p.p. to 29.5% at Day 35 p.p. At the same time, the relative number of mesenchymal cells decreased from 55 to 13%. The diameter of the seminiferous tubules showed a peak of 92 microns at Day 16 p.c., decreased to 44 microns at Day 1 p.p. and increased again to 204 microns at Day 33 p.p. These results show that, except for the Leydig cells, the proliferative activity of testicular cell types is highest during the pre- and early postnatal period. The major outgrowth of the Leydig cell population occurs around the fourth week after birth. The results are in accordance with the hypothesis that the mesenchymal cells are the progenitors of Leydig cells.

Animals↗
PubMed1999

[Leydig cell tumor: report of 2 cases].

Tumors from the gonadal stroma represent 4% among testicular tumors. Leydig cell tumors are the most common neoplasms among them and account for 1-3% of all testicular tumors. Two cases of testicular Leydig cell tumors in adult patients are presented. Presentation, diagnosis and therapeutic aspects are discussed. Both were treated with radical orchiectomy through an inguinal approach. Cas 1 was diagnosed in a cryptorchid testis and developed hepatic metastasis that were successfully treated with chemotherapy. Cas 2 was incidentally diagnosed on ultrasound. Both of them remain alive and free of disease.

Humans↗
PubMed1999

The role of Wilms' tumor genes.

The constitutional chromosomal deletion within the short arm of one copy of chromosome 11, at band p13, which often correlated with WAGR syndrome consisting of Wilms' tumor with aniridia, genitourinary malformation, and mental retardation, provided the first clue to the genetic events in the development of Wilms' tumor. WT1 gene is encoded by 10 exons, resulting in messenger RNA subject to a complex pattern of alternative splicing. WT1 gene encodes a zinc finger transcription factor, which binds to GC-rich sequences and functions as a transcriptional activator or repressor for many growth factor genes. WT 1 protein is mainly expressed in developing kidney, testis, and ovary, indicating that it is involved in the differentiation of genitourinary tissues, all thought to be the sites of origin of Wilms' tumor. The point mutation of WT1 results in Denys-Drash syndrome. The other Wilms' tumor gene, WT2 at 11p15.5, is linked to Beckwith-Wiedemann syndrome. The possibility that WT1 is involved in the etiology of rhabdoid tumor of the kidney was discussed. WT1 is expressed in immortalized hematologic cells such as EBV-LCL and hematologic malignancies, but not in PBL or IL-2L. High level WT1 expression in leukemia cells and a poor prognosis are linked in patients with leukemia, making the gene a novel marker for leukemia cells. A correlated expression between WT1 and mdr-1 in vincristine resistant cells indicates a close relation with multi-drug resistance and is a promising diagnostic marker for chemoresistance in hematologic malignancies.

Animals↗
PubMedDate not supplied

Neonatally administered diethylstilbestrol retards the development of the blood-testis barrier in the rat.

Newborn rats were treated with 10 microg of diethylstilbestrol (DES) on alternate days from the 2nd to the 12th postnatal day, and the testes were sequentially examined up to 105 days of age by light, electron, and confocal laser microscopy. In control rats, spermatozoa and step 19 spermatids were observed in stage VIII seminiferous tubules at 56 days of age. Spermatogenic cells in DES-treated rats differentiated normally from birth until 21 days of age, after which differentiation continued only to the pachytene-spermatocyte stage. From this age onward, spermatogenic cells older than pachytene spermatocytes were not found until 56 days of age. After this point, the cells resumed differentiation and finally became spermatozoa by 91 days of age; that is, 35 days later than control rats. Electron and confocal laser microscopy showed that in the normal rat, the formation of the ectoplasmic specialization between adjoining Sertoli cells was observed as early as 20 days of age. In contrast, the specialization was not formed until 56 days of age in DES-treated rats. Furthermore, the delay in functional maturation of this structure as the blood-testis barrier was confirmed by intercellular tracer experiments. It is clear that neonatal administration of DES delayed the establishment of the blood-testis barrier for 4 weeks. Consequently, during this period, pachytene spermatocytes were exfoliated from the seminiferous epithelium without completion of meiosis.

Aging↗