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)

Essentially all of the selenium in the rat spermatozoon is bound to a polypeptide of Mr 15,000-17,000 confined to the capsule that surrounds the sperm mitochondria. Isoelectric focussing of isolated 75Se-labelled, carboxymethylated mitochondrial capsule protein (MCP) reveals the presence of at least four radioactive components, with a predominant charge isomer at pI4.6. The sperm selenoprotein appears to be identical with MCP, as judged by the exact coincidence of radioactivity and protein stain during two-dimensional electrophoresis. The temporal pattern of 75Se-labelling of rat caput epididymal spermatozoa after intratesticular 75Se injection suggests that maximum incorporation of 75Se into MCP occurs in step 7-step 12 spermatids and that 75Se uptake ceases during step 15 of spermiogenesis. The developmental appearance of sperm selenoprotein in rat testis therefore appears to lag several days behind that reported for MCP in mouse testis, suggesting the presence of selenium-free MCP in immature germ cells. SDS gel electrophoretic analysis of testis subcellular fractions 24 h after 75Se injection into rat testis at 21, 28 and 90 days of age indicates that sperm selenoprotein first appears in very low concentration during late meiosis and that its concentration increases sharply during early spermiogenesis. Additional 75Se-labelled polypeptides were detected on the gels, most of them of higher molecular weight than MCP. At least two of these (Mr 47,000 and 54,000) displayed a marked decrease in labelling between 5 and 24 h after injection into adult testis, coincident with a comparable increase in 75Se-labelled MCP, indicating that they may be precursors of MCP.
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PMID:A developmental study of rat sperm and testis selenoproteins. 344 22

When androgen-binding protein (ABP) in unfractionated immature (20-day old) male rat serum was covalently labeled with the site-specific photoaffinity ligand [3H]17 beta-hydroxy-4,6-androstadien-3-one and analyzed on 5.6% polyacrylamide tube gels containing SDS (SDS-PAGE), a protein of Mr 33,700 +/- 1200 was shown to be specifically labeled. Rat epididymal ABP from unfractionated cytosol analyzed under identical conditions exhibited two androgen-specific peaks of radioactivity, Mr 49,900 +/- 600 and Mr 44,100 +/- 800, which correspond to the previously described subunits of ABP. The apparent molecular weight differences between serum and epididymal ABP were further assessed on preparations of serum ABP that had been partially purified by chromatography on Affi-Gel blue (to remove albumin) and on Sephadex G-150 (to remove other proteins). When these preparations of ABP were photolabeled and analyzed by SDS-PAGE as above, two subunits of Mr 61,700 +/- 1300 and Mr 47,100 +/- 700 were resolved. Serum and epididymal ABP were further purified by androgen affinity chromatography. When these preparations were subjected to SDS-PAGE on slab gels containing 10% polyacrylamide and identified by fluorography of photolabeled ABP or by immunochemical localization following electrophoretic transfer to nitrocellulose, differences in the apparent molecular weight of ABP from the two sources persisted. Immunochemical localization studies on ABPs that had been desialylated with neuraminidase indicated that there was an increased mobility of the subunits, as one would anticipate from removal of carbohydrate. Differences in apparent molecular weight of ABPs from the two sources are likely due to differences in glycosylation.
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PMID:The apparent molecular weight of androgen-binding protein (ABP) in the blood of immature rats differs from that of ABP in the epididymis. 366 61

The tissular origin of alkaline phosphatase was evaluated in canine seminal plasma. Alkaline phosphatase activity was most concentrated in the first fraction of the split ejaculate and was virtually undetectable in the third and fourth fractions. By contrast, arginine esterase, a known marker of dog prostatic secretion, was present in similar concentrations in all fractions of the split ejaculates analyzed by SDS gel electrophoresis. Similarly, arginine esterase was very abundant in secretory granules prepared from dog prostate homogenates, whereas these granules contained virtually no alkaline phosphatase. Among male sex accessory organs, alkaline phosphatase activity was very high in the epididymis and much lower in the testis and prostate. Furthermore, the specific activity in epididymal fluid collected from the cauda epididymis was about 10 times higher than in the corresponding epididymal homogenates. These results show that the major portion of alkaline phosphatase in dog seminal plasma does not come from the prostate but from the epididymis.
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PMID:Origin of alkaline phosphatase of canine seminal plasma. 377 20

Isolated adipocytes from rat epididymal fat-pads were incubated with [32P]Pi, and intracellular phosphoproteins were then analysed by SDS/polyacrylamide-gel electrophoresis and autoradiography. A phosphorylated polypeptide of apparent Mr 46,000 was identified as the alpha-subunit of branched-chain 2-oxo acid dehydrogenase complex by immunoprecipitation using antiserum raised against the homogeneous E1 component of branched-chain 2-oxo acid dehydrogenase complex. Immunoprecipitation of this phosphoprotein is blocked in a competitive manner by purified branched-chain 2-oxo acid dehydrogenase complex. Peptide mapping of the isolated phosphoprotein indicates that two sites on the polypeptide are phosphorylated in the intact cells. Addition of branched-chain 2-oxo acids to the incubation medium causes diminution in the extent of labelling of both phosphorylation sites on the alpha-subunit, an effect presumably mediated via their known inhibitory action on branched-chain 2-oxo acid dehydrogenase kinase. These observations provide direct evidence for phosphorylation of branched-chain 2-oxo acid dehydrogenase complex in intact cells.
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PMID:Phosphorylation of branched-chain 2-oxo acid dehydrogenase complex in isolated adipocytes. Effects of 2-oxo acids. 379 71

Cultured preadipocytes from rat epididymal fat pads were able to bind, internalize, and degrade human plasma very-low-density lipoproteins (VLDL) more efficiently than low-density lipoproteins (LDL). VLDL, but not LDL, activated acyl-CoA: cholesterol acyltransferase (ACAT) and increased cholesterol accumulation in these cells. However, trypsin-treated VLDL (T-VLDL) lost the capacity to bind, activate ACAT, and increase cholesterol accumulation. After the treatment of VLDL with trypsin, SDS/polyacrylamide-gel electrophoresis and immunoblotting showed that apolipoprotein E (apo E) was completely degraded, whereas apolipoprotein CII (apo C-II) was preserved. ApoE complexed with dimyristoyl phosphatidylcholine (DMPC) was able to complete with VLDL for binding to the cells. Although T-VLDL did not bind to the preadipocytes, these cells accumulate triacylglycerols from T-VLDL, presumably after lipolysis, as efficiently as from native VLDL. Rat smooth muscle cells and skin fibroblasts also bind and metabolize human VLDL better than LDL. However, human skin fibroblasts and omental preadipocytes metabolized LDL better than VLDL. These studies indicate that rat tissues can recognize and metabolize apoE-containing human plasma VLDL although they cannot recognize human LDL.
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PMID:Metabolism of apolipoprotein E-containing human plasma lipoproteins by rat and human cells in culture. 382 33

A novel method is described for measuring the incorporation of radiolabelled amino acids into rat adipose tissue lipoprotein lipase (LPL) in vitro. Following the incubation of epididymal fat-bodies in the presence of [3H]leucine, the radiolabelled enzyme was isolated from extracts of the delipidated tissue, in a single step, by affinity chromatography on heparin-Sepharose, SDS-PAGE of such purified enzyme preparations revealed the presence of a single radiolabelled polypeptide of molecular weight 56 000, corresponding to LPL. In the presence of insulin, the rates of incorporation into LPL and into total tissue protein were increased respectively by 2.3 fold and 1.7 fold, compared to controls. It is concluded that part of the increase in incorporation into LPL is due to the general stimulus of protein synthesis in the tissue by insulin. Additionally insulin may either specifically increase the rate of synthesis or decrease the rate of degradation of the enzyme.
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PMID:The effect of insulin on the synthesis of lipoprotein lipase in rat adipose tissue. 391 May 29

Tri[14C]acylglycerol-labelled chylomicrons, obtained from cannulated mesenteric lymph of streptozotocin-diabetic donor rats, when intravenously injected into non-diabetic recipient rats, disappeared from the circulation at a significantly slower rate than similarly prepared tri[14C]acylglycerol chylomicrons from non-diabetic donor rats (t1/2, 5.6 +/- 0.7 vs. 3.2 +/- 0.5 min-1, P less than 0.02). The appearance of labelled lipolysis products among plasma lipids (free fatty acid, cholesterol ester and phospholipid fractions) was delayed, indicating decreased availability for lipolysis of the chylomicron-borne triacylglycerol of diabetic origin. Tissue distribution of triacylglycerol, 15 min after the injection of chylomicrons to recipient rats, disclosed a 4-5-fold increase in uptake by muscles (heart and diaphragm) in relation to adipose tissues (epididymal and perirenal sites), in the case of chylomicrons of diabetic derivation. Since a large share of the chylomicron triacylglycerol was taken up by the liver, this tissue was perfused with chylomicron 'remnants' prepared by partial in vitro lipolysis with purified lipoprotein lipase. The 'remnants' of diabetic derivation were taken up by the liver at a 2-3-fold slower rate than those of non-diabetic origin. Chylomicrons derived from diabetic rats were found to be similar in size but markedly depleted of E apolipoproteins as determined by SDS-polyacrylamide gel electrophoresis, isoelectric focussing and a specific immunoassay. Decreases were also seen in A-I apolipoproteins by immunoassay and isoelectric focussing. Chylomicron 'remnants' were also markedly apolipoprotein E-deficient. In vitro incubation of the 'diabetic remnants' with high-density lipoproteins raised their apolipoprotein E content approx. 3-fold and considerably increased their hepatic uptake. Injection of intact chylomicrons preincubated with high-density lipoproteins likewise increased their in vivo removal rate toward the range of that of 'non-diabetic' chylomicrons. We conclude that diabetes-induced changes in the apolipoprotein composition of the chylomicrons and chylomicron remnants play an important role in their removal from the circulation. It appears that their recognition pattern is altered, reducing their ability to interact with receptor sites in the peripheral tissues and the liver, respectively.
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PMID:Composition, removal and metabolic fate of chylomicrons derived from diabetic rats. 399 73

Monoclonal antibodies were prepared against rabbit sperm antigens by fusing P3-X63-Ag8-653 mouse myeloma cells with lymphocytes from Balb/c mice immunized with Tergitol NP-40 detergent-solubilized rabbit epididymal sperm. Ascites fluid from mice injected with two of these hybridomas (8C4.1 and 8C10.5) was negative in immobilization and agglutination methods, however, acrosome positive on methanol fixed sperm and plasma membrane positive on unfixed sperm in indirect immunofluorescence. Insemination of female rabbits with the sperm treated with either of these monoclonal antibodies resulted in significant reduction in fertility as seen by the percentage of 9-day implants/corpora lutea ratio (8C4.1, 25.7%; 8C10.5, 1.9%; and control, 64.7%). Though the antibodies inhibited in vitro binding of the rabbit sperm with zonae pellucidae of rat ova, fertilization in vivo was not affected significantly. The antibodies did not demonstrate antiblastocyst activity by immunofluorescence. Both of these monoclonal antibodies appeared to recognize the same antigen by the SDS-PAGE/Protein Blot enzyme immunobinding procedure. The antigen was of testicular origin and had a molecular weight of approximately 63,000 daltons. It is concluded that these monoclonal antibodies which were organ specific, block post-fertilization fertility by inhibiting some step necessary for viable embryo formation.
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PMID:Inhibition of fertility in rabbits by monoclonal antibodies against sperm. 618 81

Collagenase-treated isolated cells, prepared from epididymal fat pads of Sprague-Dawley rats exposed to 32Pi or (gamma-32P)-ATP, result in differences in label incorporation into peptides as determined by autoradiography of dried SDS polyacrylamide gels. 32Pi-labelled cells respond to epinephrine by increase in labeling of a 67,000-dalton band, presumably the activated lipase. (gamma-32P)-ATP exposed cells gave a dose-dependent increase in a 53,000-dalton band, a finding shared by cells exposed to cAMP in the absence of epinephrine. However, whereas, cAMP also significantly increased the labeling of an 18,000-dalton band, epinephrine had only a minor effect in the labeling of the 18,000-dalton component. Also, the degree of labeling of a 42,000-dalton band is diminished after epinephrine compared to unstimulated cells. By contrast, cAMP does not affect the labeling of the 42,000-dalton component. The localization of the 53,000- and the 18,000-dalton peptides as well as the enzyme(s) that catalyze their phosphorylation on the external surface of the fat cell is supported by studies using a number of macromolecular probes as well as by subcellular fractionation studies. The absence of such phosphopeptides or kinase activity in the infranatants of such cell suspensions eliminates the possibility that these phenomena are the result of leakage of cytoplasmic components. Thus, epinephrine appears to have effect and do not appear to be explicable simply by the release of cAMP to the extracellular compartment.
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PMID:Direct phosphorylation effects of epinephrine on the plasma membranes of intact rat fat cells. 626 72

Glycoproteins on the plasma membrane of testicular and cauda epididymidal spermatozoa have been labeled with galactose oxidase/NaB [3H]4 and sodium metaperiodate/NaB[3H]4, followed by analysis on SDS polyacrylamide gels. The major glycoprotein labeling on testicular spermatozoa has a molecular weight 110,000 whereas on cauda epididymidal spermatozoa greater than 90% of the radio-label is incorporated into proteins of molecular weight 32,000. These 32,000-mol wt X proteins are homologous with proteins of similar molecular weight purified from the epididymal secretion and which have been shown previously to be synthesized in the caput epididymidis under hormonal control. Immunofluorescence revealed that the 32,000-mol wt proteins are present on the flagellum of mature but not immature spermatozoa and that they have a patchy distribution suggesting that they are mobile within the plane of the membrane. The membrane-bound 32,000-mol wt proteins possess hydrophobic domains as revealed by charge-shift electrophoresis and they also label with a lipophilic photoaffinity probe suggesting that they are in contact with the lipid bilayer. The evidence indicates that there is a considerable reorganization of the molecular structure of the plasma membrane of spermatozoa during maturation in the epididymis and that some of the changes are brought about by a direct interaction with epididymal secretory proteins.
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PMID:Changes in plasma membrane glycoproteins of rat spermatozoa during maturation in the epididymis. 629 50


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