Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study was designed to investigate relations of gamma-Glutamyl transpeptidase (gamma-GTP) activities to morphological differentiation and maturation of rat testicular excurrent duct system including rete testis, efferent ductuli and epididymal ducts. Animals used were Wistar rats aged from 3 days to 12 weeks. Histochemical demonstration of gamma-GTP activities was carried out by the method of Rutenburg et al. (1969). Morphological differentiation of the epithelium and structure of the rete testis occurred between 2 and 3 weeks and completed by the age of 6 weeks, which was accompanied by induction and deletion of gamma-GTP activity. Morphological differentiation and maturation of the epithelium of the efferent ductuli and the epididymal ducts became evident by the age of 4 weeks and gamma-GTP was active in both epithelial cells throughout the period examined. Since the maturation of rete testis epithelium was found to proceed as observed as Sertoli cells, the origin and functions of the rete testis epithelium and Sertoli cells are considered to be identical. The simultaneous development of the efferent ductuli and the epididymal ducts suggests that both tissues originate from mesonephric ducts and have similar functions, although mature epithelial cells of both tissues are completely different.
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PMID:[Differentiation and maturation of excurrent duct system of rat testes]. 135 73

gamma-Glutamyl transpeptidase (gamma-GT), its substrate (GSH) and hydrolytic product (L-glutamic acid) were measured biochemically in mouse reproductive tissues. The epididymal caput and seminal vesicles showed the highest specific activities of gamma-GT, while GSH and L-glutamic acid were widely distributed in all tissues. Histochemically, gamma-GT displayed a strong apical and supranuclear reaction and a moderate basal activity in the ductuli efferents, a weak luminal reaction in the first, a moderate apical reaction in the second and a strong apical and supranuclear reaction in the third segment of the epididymal caput. In the epididymal corpus and cauda, the gamma-GT reaction was confined to the tubular lumina but an apical reaction was also present in the cauda. The daily administration of acivicin (12 mg/kg body weight), an irreversible inhibitor of gamma-GT, for 14 days resulted in a 60% suppression of the enzyme activity in the epididymal caput, while the gamma-GT inhibition in the kidney was greater than 95%. The treatment caused no change in the activity of alanyl aminopeptidase. Histochemically, the basal and supranuclear gamma-GT activities in the ductuli efferents and the third epididymal segment were suppressed, but the apical reactions were maintained. The in-vivo suppression of epididymal gamma-GT activity may have implications in the control of post-testicular sperm maturation.
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PMID:Distribution of gamma-glutamyl transpeptidase in the mouse epididymis and its response to acivicin. 256 39

Gamma-Glutamyl transpeptidase (gamma-GT) was studied histochemically and biochemically in the rat epididymis after castration with or without testosterone treatment, or after hemicastration and ligation of the efferent ducts. There was a strong reaction to gamma-GT in the apical part of the epithelium in the caput epididymis, while in the corpus and cauda the reaction was confined mainly to the luminal contents. Castration caused a marked decline in epithelial gamma-GT activity within 10 days. Subsequent testosterone treatment (1 mg/day for 10 days) restored gamma-GT activity in the apical surface and lumen. After hemicastration of adult rats, and after hemicastration or ligation of the efferent ducts in immature 28-day-old rats, a small but significant (P less than 0.001) decrease was observed in gamma-GT activity in the epididymal caput compared to controls. The quantities of six other enzymes (beta-N-acetylglucosaminidase, beta-galactosidase, angiotensin-converting enzyme, alanyl amino-peptidase, dipeptidyl peptidase IV, acid phosphatase) also displayed significant changes after castration and restoration of activities by testosterone treatment. However, their distribution in the caput and cauda epididymis was more even than that of gamma-GT, and the changes after castration were less drastic. It is concluded that gamma-GT is a highly sensitive androgen-dependent secretory marker in the caput epididymis and may have an important function in sperm maturation.
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PMID:Gamma-glutamyl transpeptidase in rat epididymis: effects of castration, hemicastration and efferent duct ligation. 257 65

Gamma-glutamyl transpeptidase (GGT) mRNA-IV is highly expressed in the initial segment of the rat epididymis and is regulated by testicular factors. The promoter region for GGT mRNA-IV contains five conserved polyomavirus enhancer activator 3 (PEA3)-binding motifs (5'-AGGAAG-3'). We hypothesize that PEA3 is present in the rat epididymis and is regulated by one or more testicular factors. Western blot analyses showed that a 62-kDa protein was detected in the nuclear extract from the rat initial segment at higher levels than in the distal epididymal regions. Electrophoretic mobility shift assays (EMSAs) showed that the nuclear extract specifically bound to the PEA3 motif, forming a DNA-protein complex. This complex contained the 62-kDa PEA3 protein as demonstrated by EMSAs and Southwestern analyses. Northern blot analyses and RNase protection analyses showed that PEA3 mRNA was predominantly expressed in the initial segment as compared to the distal epididymal regions and was under the regulation of testicular factors. These results suggest that PEA3 could be involved in the regulation of expression of the rat GGT mRNA-IV gene in response to testicular factors in the initial segment.
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PMID:Identification, expression, and regulation of the transcriptional factor polyomavirus enhancer activator 3, and its putative role in regulating the expression of gamma-glutamyl transpeptidase mRNA-IV in the rat epididymis. 920 98

Gamma-glutamyl transpeptidase (GGT) is an enzyme believed to play a role in the protection of maturing spermatozoa in the epididymis. Our previous studies have shown that four GGT mRNAs (I-IV) transcribed from the single-copy rat GGT gene are differentially expressed and regulated in the rat epididymis. In particular, the normal expression of GGT mRNA(IV) in the epididymal initial segment is dependent upon the presence of testicular factors. The objective of this study was to test the hypothesis that the decreased expression of GGT mRNA(IV) in the initial segment following the in vivo removal of testicular factors by efferent duct ligation (EDL) is due to a decrease in stability and/or transcription rate. The stability of the GGT mRNAs was evaluated by measuring the rate of mRNA decay. These stability studies showed that GGT mRNA(IV) exhibited a rapid initial decay that slowed at later times to a decay rate similar to that of GGT mRNAs(II,III). The decay rates were not different following sham-operation or EDL, and thus the stability of GGT mRNAs were not influenced by the in vivo loss of testicular factors. Results of transcription analysis revealed that the transcription rate of GGT mRNA(IV) in the initial segment fell by approximately 68% following a 12-hour EDL. Additionally, secondary-structure models indicate two families of folding patterns for GGT mRNA(IV), which could be the reason for the two decay regimes detected in the stability study. Thus, the decreased expression level of GGT mRNA(IV) in the initial segment following the in vivo loss of testicular factors is a function of a decreased transcription rate and intricate decay kinetics.
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PMID:Stability and transcriptional regulation of gamma-glutamyl transpeptidase mRNA expression in the initial segment of the rat epididymis. 934 48

Gamma-glutamyl transpeptidase (GGT) mRNA-IV and polyomavirus enhancer activator 3 (PEA3) mRNA are highly expressed in the initial segment of the rat epididymis, and both are regulated by testicular factors. PEA3 protein in rat initial segment nuclear extracts has been shown to bind to a PEA3/Ets binding motif, which is derived from the partially characterized GGT mRNA-IV promoter region. This suggests that PEA3 may be involved in regulating transcription from the rat GGT mRNA-IV gene promoter in the initial segment. Using DNA oligonucleotide primers and DNA sequencing analysis, an approximately 1500-basepair (bp) DNA sequence at the 5' region of the promoter was obtained. Using transient transfection, PEA3 activated transcription of the rat GGT mRNA-IV promoter only in cultured epididymal cells from the rat initial segment, but not in Cos-1 or NRK-52E cells. Promoter deletion analysis indicated that a PEA3/Ets binding motif between nucleotides -22 and -17 is the functional site for PEA3 to activate transcription of GGT promoter IV and that an adjacent Sp1 binding motif is also required to maintain promoter IV activity in epididymal cells. Transcriptional activation of promoter IV was shown to be epididymal cell-specific and PEA3-specific. In addition, PEA3 may act as a weak repressor for transcription of promoter IV, probably using a PEA3/Ets binding motif(s) distal to the transcription start site. A model of how PEA3 is involved in the regulation of transcription of GGT promoter IV in epididymal cells is proposed.
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PMID:Involvement of polyomavirus enhancer activator 3 in the regulation of expression of gamma-glutamyl transpeptidase messenger ribonucleic acid-IV in the rat epididymis. 1002 14