Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The spermicidal effect of ethylene dibromide (EDB) in bulls and rams is reviewed. Following oral or parenteral administration EDB was found to cause, by its alkylating effect in the testes of treated bulls and rams, lysis of the chromatin of the elongating spermatids during the time of somatin histones replacement by the sperm protamines. However, while in the bulls the abnormal spermatozoa issued from the affected spermatids were also collected in the ejaculates, this was not the case with treated rams. In the latter animals the abnormal spermatids seem to be phagocytized in the epididymis before their arrival in the ejaculate. In addition, whereas the alkylating effect of EDB occurred also in the upper parts of the epididymis of the bulls, causing tail and acrosome defects to the spermatozoa, in the rams such an effect seems to occur all along the epididymal duct. These differences between bulls and rams in the sites of the genital tract where the drug takes effect, and in the mechanism of this effect, reveal probable differences in the physiology of the reproductive tract between these species.
Mol Reprod Dev 1991 Jan
PMID:The spermicidal effect of ethylene dibromide in bulls and rams. 199 86

The presence and distribution of cholesterol in mature and immature epididymal spermatozoa was analyzed using filipin as a cytochemical tool in freeze-fracture replicas and thin section preparations. The polyenic-antibiotic filipin formed complexes with 3, beta -OH sterols, producing characteristic protrusions, or pits, that were heterogeneously distributed in the plasma membrane of stallion spermatozoa, revealing a specific organization in a functionally specialized area of the gamete. The acrosomal region of the sperm head presented a significantly higher density of filipin sterol complexes than the postacrosomal region, which was usually free of these complexes. The plasma membrane of the flagellum also showed filipin sterol complexes randomly distributed in freeze-fracture replicas. The strong filipin labeling observed in the membrane of spermatozoa obtained from the caput region of the epididymis decreased significantly during epididymal passage. The significance of these changes is not completely understood, but they might contribute to establishing the molecular organization necessary for sperm transit and storage in the epididymis as well as to development of motile spermatozoa that are able to fertilize the oocyte and induce normal embryonic development.
Mol Reprod Dev 1991 Feb
PMID:Distribution of filipin-sterol complexes in the plasma membrane of stallion spermatozoa during the epididymal maturation process. 200 29

The conversion of 3 beta-hydroxy-5-ene steroids by the enzyme complex 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) is an obligatory step in the biosynthesis of all classes of hormonal steroids in classical steroidogenic as well as in peripheral tissues. To develop a model more closely related to the human, we have isolated and characterized cDNA clones encoding macaque 3 beta-HSD by screening a rhesus monkey ovary lambda gt11 cDNA library using a human 3 beta-HSD cDNA probe. Nucleotide sequence of 1629 bp from overlapping cDNA clones predicts a protein of 372 amino acids with a calculated molecular mass of 41,874 (excluding the first Met). The deduced amino acid sequence of macaque 3 beta-HSD displays 79.4% and 93.9% similarity with that of bovine and human 3 beta-HSD, respectively. RNA blot analysis performed under high stringency conditions of macaque poly(A)+ RNA samples using full-length 32P-labeled macaque 3 beta-HSD cDNA revealed the presence of an approximately 1.7 kb mRNA species in classical steroidogenic tissues, namely the ovary, testis and adrenal glands as well as in several peripheral tissues including the liver, kidney and epididymis. Computer analysis of the deduced macaque 3 beta-HSD protein sequence predicts the presence of an NH2-terminal membrane-associated segment as well as four additional membrane-spanning segments, thus suggesting that 3 beta-HSD is an integral protein. The availability of macaque cDNA should permit detailed studies concerning the tissue-specific expression as well as the hormonal regulation of 3 beta-HSD mRNA in classical steroidogenic glands as well as in peripheral tissues which are an important site of steroidogenesis in primates.
Mol Cell Endocrinol 1991 Feb
PMID:Characterization of macaque 3 beta-hydroxy-5-ene steroid dehydrogenase/delta 5-delta 4 isomerase: structure and expression in steroidogenic and peripheral tissues in primate. 205 Feb 70

Mouse spermatozoa were obtained from the testis and caput, corpus, and cauda epididymis incubated for 2 h in capacitation medium and a single spermatozoon from the capacitated samples microinjected into the pervitelline space of mature mouse oocytes. Spermatozoa from the testis were unable to fertilize oocytes and few spermatozoa from the caput were capable of fertilization (0-7% depending on the method of preparation). Similar fertilization rates (30-45%) were obtained with spermatozoa with forward progressive motility from the proximal and distal corpus and the cauda epididymis, but those that were vibratory or with local circular motility had significantly reduced fertilizing capacity (6-10%). The capacity of spermatozoa from the different regions of the testis and epididymis to bind to zona-free oocytes followed the same pattern as fertilization rate after microinjection. There was a progressive increase in acrosome reactions after 2 h incubation in capacitation medium in samples obtained from the testis to the cauda epididymis. Maturation of the capacity to bind to the perivitelline membrane and to develop forward progressive motility, rather than the capacity to acrosome react, appears to govern the fertilization of oocytes in which the zona has been bypassed by microinjection. These characteristics are obtained in the proximal segment of the corpus. However, there was evidence that the embryo developmental capacity of oocytes fertilized by spermatozoa from the higher segments of the epididymis is reduced, particularly in oocytes fertilized by caput spermatozoa. These observations suggest that sperm microinjection may have only a limited benefit for improving fertilization rates for men with high epididymal obstructive azoospermia.
Mol Reprod Dev 1991 May
PMID:Fertilizing capacity of epididymal and testicular spermatozoa microinjected under the zona pellucida of the mouse oocyte. 205 85

Human sex steroid-binding protein (hSBP) has been purified from late-pregnancy serum and labelled either by iodination (125I) or by photoaffinity with [3H]delta 6-testosterone. Using a micromanipulator, each labelled protein was separately injected into the lumen of epididymal tubules isolated from the head epididymis of the cynomologus monkey (Macaca fascicularis). Tubules were sampled from 3 to 90 min after the injection and processed for electron microscope autoradiography. Localization of the label occurred over the epididymal epithelium whichever tracer was used. The labelling was not randomly distributed over the different cell types constituting the epithelium, since only the 'principal cells' exhibited a silver grain count significantly greater than the background count. In these cells, labelled protein was found over endocytic organelles (coated structures, endosomes, multivesicular bodies and the trans Golgi network) and nuclei (including the nuclear envelope). Quantitative analysis demonstrated the same pattern of cellular and subcellular distribution for each tracer. Pretreatment with excess unlabelled protein significantly reduced the uptake of radioactivity by the principal cells, demonstrating the specificity of this phenomenon. This is the first study to show direct histological evidence for the internalization of hSBP in the primate epididymis, consistent with earlier immunohistochemical or biochemical localization of this protein. It is concluded that head epididymal cells are able to take up labelled hSBP across their apical membrane. The mechanism of internalization seems to involve endocytosis by the principal cells and leads to labelling of the nuclear compartment. This is strikingly similar to the pattern of uptake of rat androgen-binding protein (rABP) by rat epididymal cells previously demonstrated by our group. To what extent the chemical and structural homology between hSBP and rABP can be held responsible for the common cytophysiological behaviour of these sex steroid-binding proteins remains to be determined.
J Mol Endocrinol 1990 Dec
PMID:Internalization of human sex steroid-binding protein in the monkey epididymis. 212 29

This study was undertaken to determine the role of calcium ion, a key regulator of the intensity and form of motility in mature demembranated sperm, in the development of motility during passage through the bovine epididymis. Cellular calcium levels in bovine caput and cauda epididymal spermatozoa were measured with three different techniques. 45Ca2+ uptake measurements revealed that net calcium uptake and Ca2(+)-Ca2+ exchange in caput spermatozoa were about 2 to 3 times higher than in caudal spermatozoa. Intracellular free calcium determination with the calcium fluorophore Fura 2 showed that the levels were 6 times higher in caput spermatozoa. The values for caput and caudal sperm were 875 +/- 55 nM (n = 15) and 155 +/- 6 nM (n = 24), respectively. Total cellular calcium levels quantitated by atomic absorption were 626 +/- 30 (n = 48) and 304 +/- 19 (n = 46) ng/10(8) sperm in caput and caudal epididymal sperm, respectively. At least one of the reasons for the high calcium content of caput epididymal sperm is the result of a higher rate and extent of mitochondrial calcium accumulation in caput compared to caudal sperm. Mitochondrial calcium uptake rates measured in digitonin permeabilized cells revealed uptake rates 2- to 3-fold higher in caput compared to caudal sperm. However, mitochondrial calcium efflux rates were identical in caput and caudal epididymal sperm. The efflux rates in both cell types were unaffected by external sodium levels but were found to be proportional to pH. Alkalinization or acidification of internal pH of intact sperm resulted in a corresponding lowering or elevation of cytoplasmic free calcium levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Reprod Dev 1990 Feb
PMID:Changes in the mitochondrial calcium influx and efflux properties are responsible for the decline in sperm calcium during epididymal maturation. 215 28

Spermatozoa from the caput epididymis are known to be much less capable of fertilization when compared to sperm from more distal segments of the epididymis. The purpose of this study was to determine if two micromanipulative techniques, zona drilling (ZD) and a modification of partial zona dissection (PZD), could be used to enhance fertilization with caput epididymal sperm. A mouse in vitro fertilization model was used. Inseminating oocytes with 500-1,000 sperm/oocyte from the cauda epididymis as a control resulted in fertilization of 98 of 300 (32.6%) oocytes. Of those fertilized, 47 developed to the blastocyst stage (47.9%). Caput sperm fertilized 13 of 116 (11.2%) nonmanipulated oocytes. Only 1 of 13 developed into a blastocyst, while with oocyte ZD, caput sperm fertilized 24 of 144 (16.7%) oocytes, 50% of those fertilized developing to blastocyst (P = 0.0129). When modified PZD was performed on oocytes, only one of 23 was fertilized, with no blastocyst development. These results indicate that acid Tyrode ZD enhances both fertilization and early embryonal development when caput epididymal sperm are used for insemination. These mouse studies suggest that ZD or other micromanipulation techniques may prove clinically useful in men with proximal epididymal obstruction where only caput sperm are available.
Mol Reprod Dev 1990 Dec
PMID:Zona drilling enhances fertilization by mouse caput epididymal sperm. 226 95

Four abundant cDNA clones have been isolated from a rat epididymal cDNA library. Northern blot analysis has shown that these clones partially encode 4.5 kb, 2.8 kb, 1.2 kb and 0.85 kb mRNAs and that their expression is not detectable in total RNA preparations from heart, kidney, liver or testis. Fourteen days after castration the levels of the 2.8 kb, 1.2 kb and 0.85 kb transcripts were greatly reduced whereas the 4.5 kb mRNA was undetectable. Subsequent treatment of castrated rats with testosterone for 1 day resulted in a complete restoration of the pre-castration steady-state levels of the 2.8 kb and 0.85 kb mRNAs, restoration of the 4.5 kb mRNA to 70% of pre-castration levels, and a slight over-induction of the 1.2 kb mRNA. Analyses of separate regions of the epididymal tract showed that expression of the 2.8 kb and 1.2 kb mRNAs increased towards the distal end of the epididymis, while the 4.5 kb and 0.85 kb transcripts were primarily synthesised in the caput region.
Mol Cell Endocrinol 1990 Nov 12
PMID:Analysis of major androgen-regulated cDNA clones from the rat epididymis. 228 80

A cDNA clone encoding androgen-dependent proteins secreted by the mouse epididymis was isolated by screening a cDNA library using differential hybridization, according to the selective expression of the mRNA in the normal but not in the castrated mouse. Translation of mRNA hybrid-selected by this 1.4 kb clone (M53) yielded proteins of Mr 26,000 which were processed in vitro in the presence of microsomal membranes into proteins of Mr 24,000. Northern blot analysis of epididymal total RNA revealed at least two populations of mRNA (1.4 and 1.8 kb) homologous to the M53 clone, which were restricted to the caput epididymidis. Studies in vivo demonstrated that testosterone regulates the concentration of these mRNA populations. Analysis of epididymal total RNA from ten individual animals provided no evidence that the M53 mRNA populations are the products of allelic variants of a gene. Southern analysis of mouse genomic DNA revealed single bands with most of the tested restriction enzymes. Furthermore, cross-hybridization to the M53 cDNA revealed homologous mRNA species in rat, human, rabbit, ram and boar epididymal RNA.
J Mol Endocrinol 1990 Feb
PMID:Molecular cloning of a cDNA for androgen-regulated proteins secreted by the mouse epididymis. 232 85

The gene encoding the opioid peptide precursor preproenkephalin is expressed at high levels in the initial segment of the adult rat epididymis. Expression is localized to principal cells, the secretory epithelial cells lining the epididymal duct. During development, epididymal proenkephalin mRNA levels show a pronounced increase at about 44 days of age, coincident with the initial entry of spermatozoa into the epididymal lumen. Hypophysectomy leads to a 60-fold decrease in epididymal proenkephalin mRNA levels. Testosterone replacement can prevent this decline in a manner consistent with an effect upon spermatogenesis. Castration studies demonstrate that a gonadal factor other than testosterone directly regulates epididymal proenkephalin expression, and the results of efferent duct ligation suggest that this factor must be supplied through an intact connection of the testis and epididymis. Proenkephalin mRNA levels in the epididymis correlate with the decline and reappearance of spermatozoa induced by the alkylating agent busulphan. Thus, the developmental profile of proenkephalin expression, coupled with the results of both surgical and pharmacological manipulations of the reproductive tract, indicate that spermatozoa, or a spermatozoa-associated factor, regulate proenkephalin gene expression in the epididymis.
Mol Endocrinol 1990 Jan
PMID:A spermatozoa-associated factor regulates proenkephalin gene expression in the rat epididymis. 232 61


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>